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Math 8 · Mathematics
Rational numbers · Numbers

Fraction Word Problems

Before you start, make sure you know: Operations with rational numbers (Math 7)
Before you start, make sure you know: Concept (Math 7)

Sofia's data plan has a limit. In week 1 she used $\frac{1}{2}$ of her data. In week 2 she used $\frac{1}{3}$ of what was left. Her brother says, "So she used $\frac{1}{2} + \frac{1}{3} = \frac{5}{6}$ of the plan!" Is he right?

Fraction word problems look scary until you notice that almost all of them are one of a few types. One tool solves nearly every type: draw a bar for the whole and cut it into pieces. In this section you will learn to spot each type and draw it. At the end we'll come back to Sofia.

Fraction of a quantity

"$\frac{3}{5}$ of the 40 students in the class prefer video games." Finding a fraction of something means multiplying:

$$\frac{3}{5} \text{ of } 40 = 40 \times \frac{3}{5} = \frac{120}{5} = 24$$

In practice: divide by the denominator (how big is one part?) and multiply by the numerator (how many parts do you take?).

A bar split into 5 equal parts of 8 each (total 40), with 3 parts highlighted that add up to 24. Total: 40 88888 3 parts → 3 × 8 = 24 40 ÷ 5 = 8 in each part
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In an 8th grade class there are 28 students. A survey was carried out on their leisure preferences and it was discovered that $\frac{3}{7}$ of the class prefers playing…

In an 8th grade class there are 28 students. A survey was carried out on their leisure preferences and it was discovered that $\frac{3}{7}$ of the class prefers playing video games to watching TV shows.

Calculate how many students prefer video games and how many prefer watching TV shows, assuming that everyone has chosen one of the two options.

Solve
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A streamer wants to do a live stream lasting 4 hours. He has planned the time as follows: He will dedicate $\frac{1}{5}$ of the time to chatting with viewers (Just…

A streamer wants to do a live stream lasting 4 hours. He has planned the time as follows:

  • He will dedicate $\frac{1}{5}$ of the time to chatting with viewers (Just Chatting).

  • He will dedicate $\frac{3}{4}$ of the time to playing his favorite game.

  • He will use the rest of the time to watch funny videos.

Calculate how many minutes he will dedicate to each of the three activities.

Solve
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A water tank for watering a school vegetable garden has a total capacity of 1,200 gallons. During a very hot week, $\frac{5}{6}$ of the water in the tank has been…

A water tank for watering a school vegetable garden has a total capacity of 1,200 gallons.

During a very hot week, $\frac{5}{6}$ of the water in the tank has been consumed.

  1. a) How many gallons of water have been used?
  2. b) Represent the situation graphically and calculate how many gallons are left in the tank.
1,200 gal Consumed (5/6) ? gal Left (1/6) ? gal
Solve

From the part to the whole

Now the other way around. You know how much one part is and you want the whole. "When the download reaches $\frac{3}{8}$, you have 15 GB. How big is the game?"

A bar split into 8 equal parts where 3 shaded parts represent 15 GB, 5 GB each, so the whole is 40 GB. 555 15 GB 15 ÷ 3 = 5 GB in each eighth So the whole is 8 × 5 = 40 GB

Problems often give a percent instead of a fraction. Turn it into a fraction first and the same method works.

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Your cell phone has a long-lasting battery. After using it all morning to listen to music, you notice that the battery indicator shows you have $25\%$ of charge left,…

Your cell phone has a long-lasting battery. After using it all morning to listen to music, you notice that the battery indicator shows you have $25\%$ of charge left, which is equivalent to the fraction $\frac{1}{4}$.

If the phone indicates that this remaining $\frac{1}{4}$ corresponds to 3 hours of use:

  1. a) How many hours of use does the battery have when it is charged to $100\%$?
  2. b) How many hours have you been listening to music?

Use the following visual diagram to help deduce the answer.

100% (4/4) = ? h 25% (1/4) = 3 h 75% (3/4) = ? h 1/4 1/4 1/4 1/4
Solve
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After a birthday party, there is some cake left over. Looking at the image, we see that $\frac{1}{4}$ of the original cake is left on the plate. If the leftover piece…

After a birthday party, there is some cake left over. Looking at the image, we see that $\frac{1}{4}$ of the original cake is left on the plate. If the leftover piece weighs 300 grams:

  1. a) How much did the whole cake weigh before the party started?
  2. b) How many grams of cake have the guests eaten?
¼ ¼ ¼ ¼ Eaten ¾ ? g Left over ¼ 300 g Whole cake ? g
Solve
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You are downloading a new video game that takes up a lot of space on the hard drive. When the download bar is $\frac{2}{7}$ complete, your internet connection drops.…

You are downloading a new video game that takes up a lot of space on the hard drive. When the download bar is $\frac{2}{7}$ complete, your internet connection drops. Upon reconnecting, the download continues and advances $\frac{3}{5}$ of what was left to download.

  1. a) What fraction of the total game has been downloaded after the second stage?
  2. b) If there are still 4 GB left for the full download to finish, how much space does the video game take up in total?
Solve

Comparing fractions of different wholes

Who did better: the player who made 12 of 15 free throws or the one who made 17 of 20? Write each result as a fraction, simplify it, and then rewrite both with a common denominator (use the LCM of the denominators). With equal denominators you can compare numerators.

Two bars of the same length: one filled to 3/4 (15/20) and one filled to 7/10 (14/20), showing that 3/4 is larger. Emma: 9 of 12 = 3/4 = 15/20 Aaliyah: 14 of 20 = 7/10 = 14/20 Emma is ahead
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Two friends, Alex and Mia, are competing to see who completes the achievements of a new video game first. Alex has completed $\frac{2}{3}$ of the achievements. Mia has…

Two friends, Alex and Mia, are competing to see who completes the achievements of a new video game first.

  • Alex has completed $\frac{2}{3}$ of the achievements.

  • Mia has completed $\frac{5}{8}$ of the achievements.

Represent both fractions by reducing them to a common denominator and determine: Who is currently winning the competition?

0 12 24 Alex (2/3) = 16/24 Mia (5/8) = 15/24 +1/24
Solve
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In the final of a basketball tournament, the free throw statistics of two players are compared. Player A scored 12 of the 15 free throws they took. Player B took 20 free…

In the final of a basketball tournament, the free throw statistics of two players are compared. Player A scored 12 of the 15 free throws they took. Player B took 20 free throws and scored 17.

  1. a) Write the fraction of successful shots for each player and simplify them if possible.
  2. b) Reduce the fractions to a common denominator to determine which player had better accuracy (higher proportion of successful shots).
  3. c) If player A had taken the same 20 shots as player B maintaining their success rate, how many baskets would they have scored?
Solve

Parts that add up

"In a school playlist of 60 songs, $\frac{1}{2}$ are pop, $\frac{1}{5}$ are hip-hop, and the rest are rock." All the fractions are of the same whole, so you can add them.

When the denominators are not multiples of each other, find the LCM first.

Follow these steps so you don't get lost:

Four-step cycle for fraction problems: read and draw, decide what each fraction is of, write everything as fractions of the total, then compute and check. 1. Read anddraw a bar 2. Fraction ofwhat? 3. Write all asfractions of total 4. Compute andcheck The key question in step 2: is the fraction of the total or of what's left?

If the rest has to be shared equally among several things, just split the leftover fraction evenly. For example, if $\frac{3}{10}$ is split between two crops, each gets $\frac{3}{10} \div 2 = \frac{3}{20}$.

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For the end-of-year trip, the students are selling raffle tickets. Group A has sold $\frac{1}{3}$ of the total raffle tickets. Group B has sold $\frac{2}{5}$ of the…

For the end-of-year trip, the students are selling raffle tickets.

  • Group A has sold $\frac{1}{3}$ of the total raffle tickets.

  • Group B has sold $\frac{2}{5}$ of the total.

  • Group C has sold the rest.

  1. a) Calculate what fraction of the total raffle tickets Group A and Group B have sold together.
  2. b) What fraction of the raffle tickets has Group C had to sell?
Solve
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Maria has a music playlist with 120 songs. $\frac{1}{2}$ of the songs are Pop. $\frac{1}{3}$ of the songs are Rock. The rest are Electronic Music. a) How many songs are…

Maria has a music playlist with 120 songs.

  • $\frac{1}{2}$ of the songs are Pop.

  • $\frac{1}{3}$ of the songs are Rock.

  • The rest are Electronic Music.

  1. a) How many songs are Pop and how many are Rock?
  2. b) What fraction of the total do the Electronic Music songs represent? (Remember to simplify the result if possible).
Solve
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A community urban garden of $600 m^2$ is divided to grow different vegetables. $\frac{1}{4}$ of the land is dedicated to tomatoes and $\frac{2}{5}$ of the land to…

A community urban garden of $600 m^2$ is divided to grow different vegetables. $\frac{1}{4}$ of the land is dedicated to tomatoes and $\frac{2}{5}$ of the land to peppers. The rest of the land is divided into equal parts to plant lettuces and carrots.

  1. a) What fraction of the total garden is dedicated to lettuces?
  2. b) How many square feet does the carrot crop occupy?
Total Area = 600 m² Tomatoes 1/4 Peppers 2/5 Lettuces ? / ? Carrots ? ft² Rest of the land (Divided into 2 parts) 💡 The grid divides the total into 20 parts (LCM of 4 and 5) to make visualization easier.
Solve

How many pieces fit?

"A ribbon is 9 feet long. You cut it into pieces $\frac{3}{4}$ ft long. How many pieces do you get?" Now you are asking how many times a fraction fits into a number, which is a division: $9 \div \frac{3}{4}$.

A 3-foot ribbon cut into 4 pieces of 3/4 foot each, showing that 3 divided by 3/4 equals 4. 3/43/43/43/4 1 ft1 ft1 ft 3 ÷ 3/4 = 3 × 4/3 = 4 pieces
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In a perfume factory they have a large tank with 24 gallons of lavender essence. They have to bottle all the contents into small bottles for sale. a) If each bottle has…

In a perfume factory they have a large tank with 24 gallons of lavender essence. They have to bottle all the contents into small bottles for sale.

  1. a) If each bottle has a capacity of $\frac{3}{4}$ of a gallon, how many bottles can they fill completely?
  2. b) If they change the format and use smaller bottles of $\frac{3}{8}$ of a gallon, how many bottles will they need now? Explain the relationship between the result of section a) and that of b).
24 gal ⅜ gal ¾ gal a) ? bottles ⅜ gal b) ? bottles
Solve

Fraction of what is left

This is the sneakiest type. "You use $\frac{1}{3}$ of your battery in the morning and $\frac{1}{4}$ of what was left in the afternoon." The second fraction is not of the whole battery. It is of the remainder.

Bar showing 1/2 used in week 1, then the remaining half split in 3 parts where one part (1/6 of the total) is used in week 2, leaving 1/3. 1) Week 1: 1/2 of the total used 1/2left 1/2 2) Week 2: 1/3 of what was left (split the 1/2 into 3 parts) used 1/21/61/61/6 Week 2: 1/3 × 1/2 = 1/6 of the total Used: 1/2 + 1/6 = 2/3. Left: 1/3

Back to Sofia: week 2 was $\frac{1}{3}$ of the $\frac{1}{2}$ that was left, so she used $\frac{1}{3} \times \frac{1}{2} = \frac{1}{6}$ of the whole plan. In total she used $\frac{1}{2} + \frac{1}{6} = \frac{2}{3}$, not $\frac{5}{6}$. Her brother added fractions of different wholes.

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Imagine you have a monthly cell phone data plan. During the first week of the month, you have used $\frac{1}{3}$ of your total data watching streaming videos. During the…

Imagine you have a monthly cell phone data plan. During the first week of the month, you have used $\frac{1}{3}$ of your total data watching streaming videos. During the second week, you have used $\frac{2}{5}$ of what you had left browsing social media.

  1. a) What fraction of your total data have you used in these two weeks?
  2. b) If you still have 2 GB available for the rest of the month, how many GB did your plan have initially?
1st WEEK 1/3 REMAINDER 2/3 2/5 OF THE REMAINDER 2 GB REMAINING ? GB TOTAL PLAN
Solve
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A group of students is organising an end-of-year trip. To finance it, they decide to sell raffle tickets. The first month they sell $\frac{3}{8}$ of the total tickets.…

A group of students is organising an end-of-year trip. To finance it, they decide to sell raffle tickets. The first month they sell $\frac{3}{8}$ of the total tickets. The second month, they make an effort and sell $\frac{2}{3}$ of the tickets they had left to sell.

  1. a) What fraction of the total tickets do they still have left to sell after the second month?
  2. b) If in the end they have 150 unsold tickets left over, how many tickets did they have at the beginning for the raffle?
Total tickets (8/8) 3/8 1st month Remainder (5/8) 2/3 2nd month 1/3 150 left over
Solve
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Three friends, Alex, Mia, and Daniel, decide to buy a joint birthday present. Alex contributes $\frac{2}{5}$ of the total price of the present. Mia decides to put in…

Three friends, Alex, Mia, and Daniel, decide to buy a joint birthday present. Alex contributes $\frac{2}{5}$ of the total price of the present. Mia decides to put in $\frac{3}{4}$ of what was left to pay for the present after Alex's contribution. Finally, Daniel puts in the remaining $\$15$ to complete the price.

Determine:

  1. a) What fraction of the total did Daniel pay?
  2. b) What was the total price of the present?
  3. c) How much money did each of the other two friends put in?
Alex Mia Daniel Remainder 2/5 of the total 3/4 of the remainder $15 (1/4 of the remainder) Total Price of the Present = ?
Solve

The same fraction again and again

A bouncing ball rises to $\frac{3}{4}$ of the height it fell from. After two bounces it reaches 36 in. How high was it dropped? Each bounce multiplies the height by $\frac{3}{4}$, so after two bounces the height is $\frac{3}{4} \times \frac{3}{4} = \frac{9}{16}$ of the start. Then it is a "part to whole" problem.

Three bars showing a ball's heights: 64 inches on the drop, 48 inches after bounce 1, and 36 inches after bounce 2, each 3/4 of the one before. 64 in.48 in.36 in. dropbounce 1bounce 2 × 3/4× 3/4

The same idea works for any fraction. If a ball rises to $\frac{3}{5}$ of the previous height each time, two bounces give $\frac{3}{5} \times \frac{3}{5} = \frac{9}{25}$ of the start. If it rises to $\frac{2}{3}$ each time, three bounces give $\frac{2}{3} \times \frac{2}{3} \times \frac{2}{3} = \frac{8}{27}$ of the start. Count the bounces to know how many times to multiply.

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A very elastic rubber ball is dropped from a certain height. Due to the loss of energy, each time it bounces it only rises to $\frac{3}{5}$ of the height from which it…

A very elastic rubber ball is dropped from a certain height. Due to the loss of energy, each time it bounces it only rises to $\frac{3}{5}$ of the height from which it fell on the previous bounce.

After bouncing twice (it falls, bounces, rises, falls again, bounces and rises), the ball reaches a height of 54 in.

  1. a) What fraction of the initial height does the height after the second bounce represent?
  2. b) From what initial height was the ball dropped?
h₀ = ? h₁ = 3/5 · h₀ h₂ = 54 in. Drop 1st Bounce 2nd Bounce × 3/5 × 3/5
Solve
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A competition basketball is dropped from a certain height. Due to the loss of energy, on each bounce the ball rises to $\frac{2}{3}$ of the height from which it fell on…

A competition basketball is dropped from a certain height. Due to the loss of energy, on each bounce the ball rises to $\frac{2}{3}$ of the height from which it fell on the previous bounce. After hitting the ground for the third time, the ball rises to a height of $56$ in.

Calculate the initial height from which the ball was dropped. Express the result in feet.

1 2 3 h₀ = ? h₁ = 2/3 h₀ h₂ = 2/3 h₁ h₃ = 56 in.
Solve
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A famous video game streamer observes how the views of one of her old videos decrease over time. The first month, the video receives a certain number of views. The…

A famous video game streamer observes how the views of one of her old videos decrease over time.

The first month, the video receives a certain number of views.

The second month, the views decrease by $\frac{1}{4}$ compared to the previous month.

The third month, the views drop by $\frac{2}{5}$ compared to those in the second month.

If in the third month the video had $10.800$ views.

How many views did the video have in the first month?

Views ? Month 1 1/4 Month 2 2/5 10.800 Month 3
Solve

Working backward to the whole

Many problems give you the leftover amount and ask for the whole. The plan is always the same: find the fraction used, subtract from 1 to get the fraction left, match that fraction to the known amount, and then find the whole.

A bar for an 8-mile trail run split into 4 equal parts: the first quarter is run before the water break, the next two quarters are 2/3 of what was left, and the last quarter, 2 miles, remains. 1/42/3 of the rest = 2/4left 1/4 Covered: 1/4 + 2/4 = 3/4. Left: 1/4. 1/4 of the trail = 2 mi, so the trail is 8 mi.
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In an 8th-grade class, a vote is held to choose the destination for the end-of-year trip. $\frac{1}{3}$ of the students vote to go to a theme park. $\frac{2}{9}$ vote to…

In an 8th-grade class, a vote is held to choose the destination for the end-of-year trip. $\frac{1}{3}$ of the students vote to go to a theme park. $\frac{2}{9}$ vote to go to the mountains. The rest of the class, which is 12 students, vote to go to the beach.

  1. a) What fraction of the class voted to go to the beach?
  2. b) How many students are there in total in the class?
  3. c) How many students voted for the theme park and how many for the mountains?
Theme park (¹/₃) Mountains (²/₉) Beach (Remainder) 12 students Total class = ?
Solve
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A cyclist is doing a mountain stage. They have covered $\frac{3}{7}$ of the total route when they stop for refreshments. They continue their ride and cover $\frac{2}{5}$…

A cyclist is doing a mountain stage. They have covered $\frac{3}{7}$ of the total route when they stop for refreshments. They continue their ride and cover $\frac{2}{5}$ of what was left until they reach a mountain pass. At that point, they check their GPS and see that they still have $18$ miles left to reach the finish line.

How many miles is the stage in total and how many miles did they cover in the first section before the refreshment stop?

Solve
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An end-of-year trip is being organized at a middle school. Initially, $\frac{1}{6}$ of the 8th-grade students decide not to go. Of the rest of the students who were…

An end-of-year trip is being organized at a middle school. Initially, $\frac{1}{6}$ of the 8th-grade students decide not to go. Of the rest of the students who were interested, $\frac{2}{15}$ finally drop out because the dates do not suit them. If in the end $130$ students go on the trip:

  1. a) What fraction of the total 8th-grade students finally went on the trip?
  2. b) How many students are there in total in 8th grade?
  3. c) How many students dropped out because of the dates?
Total 8th-grade students Not going (¹/₆) Interested Dropped out (²/₁₅) Going on the trip 130 students
Solve

Rates, mixtures, and area

The hardest problems combine the ideas above. Here are three patterns.

Working together. If a hose fills a pool in 3 hours, it fills $\frac{1}{3}$ of the pool each hour. That is its rate. When two hoses run at the same time, add their rates. The part of the job done is rate × time.

A tank bar split into 6 equal parts: hose 1 fills 2 parts per hour, hose 2 fills 1 part per hour, so after one hour 3 of 6 parts are full. Blue: hose 1 (1/3 per hour). Orange: hose 2 (1/6 per hour). Together: 1/3 + 1/6 = 1/2 of the tank per hour

Mixtures. The amount of a substance in a can is fraction × volume. Find that amount for each can, add them, and divide by the total volume. A mixed number such as $1\tfrac{1}{2}$ gallons is easiest to use as an improper fraction, $\frac{3}{2}$.

Area. If a problem gives one side of a rectangle and the area of one part, first find what fraction of the plot that part is, then the total area, and finally use $\text{area} = \text{length} \times \text{width}$ to get the missing side.

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A water tank for watering an organic garden is filled by two taps. Tap A, which has a higher flow rate, can fill the empty tank in 4 hours. Tap B, which is older and…

A water tank for watering an organic garden is filled by two taps. Tap A, which has a higher flow rate, can fill the empty tank in 4 hours. Tap B, which is older and slower, takes 6 hours to fill it completely. One day, the tank is empty and the farmer opens both taps at the same time, but after an hour and a half (1.5 h), tap A breaks down and stops pouring water.

Calculate what fraction of the tank is left to fill at that moment and how long tap B will take, working alone, to finish filling it.

Tap A 4h Tap B 6h Full (A+B) t = 1.5h Fraction? Time B?
Solve
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We are preparing two paint mixtures for an urban art mural. Can A contains a mixture of $1\frac{1}{2}$ gallons, where $\frac{1}{3}$ is blue paint and the rest is white…

We are preparing two paint mixtures for an urban art mural.

  • Can A contains a mixture of $1\frac{1}{2}$ gallons, where $\frac{1}{3}$ is blue paint and the rest is white paint.

  • Can B contains $\frac{3}{4}$ of a gallon of a mixture where $\frac{2}{5}$ is blue paint and the rest is white.

If we pour the contents of both cans into a large bucket to create a single mixture:

  1. a) What total volume of paint do we have?
  2. b) What fraction of the total volume of the new mixture corresponds to the blue paint?
1½ gal ⅓ Blue ⅔ White Can A + ¾ gal ⅖ Blue ⅗ White Can B
Solve
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A farmer has a rectangular plot of land. They dedicate $\frac{2}{5}$ of the surface area to growing wheat. Of the remaining land, they use $\frac{3}{4}$ to grow corn.…

A farmer has a rectangular plot of land. They dedicate $\frac{2}{5}$ of the surface area to growing wheat. Of the remaining land, they use $\frac{3}{4}$ to grow corn. The rest of the plot, which is $600\text{ ft}^2$, is left fallow (uncultivated).

Knowing that the plot has a width of $40$ feet, calculate the length of the plot.

Remainder (3/5 of the total) WHEAT 2/5 of the total CORN 3/4 of the remainder FALLOW 600 sq ft 40 ft Total length?
Solve

Summary

See all the exercises in this section