Exercises: Percentages

In an esports tournament, $20\%$ of the $150$ participants play on a tablet, while the rest do so on a computer. Calculate the exact number of players who use a tablet to compete.

The progress bar of your favorite video game indicates that $75\%$ of the total download has already been completed. If the complete file takes up a space of $40$ GB, how many gigabytes have already been downloaded?

Work out the following percentages mentally using the division strategies learned in class (divide by $2$ for $50\%$, by $4$ for $25\%$, and by $10$ for $10\%$):

1. a) $50\%$ of $84$ viewers in a live stream.
2. b) $25\%$ of a $400$ ounce pizza.
3. c) $10\%$ of a transit pass that costs $\$35$.

Look at the following grid that represents the plan of a recreation area in a shopping center. Each small square represents $1\%$ of the total. If the area shaded in orange is reserved for arcade games, what percentage of the total does this area occupy? Express the result also as a simplified fraction.

Some sneakers that cost $\$60$ have a $15\%$ discount today. How many dollars do you save by buying them today? What is the final price you will pay for them?

When buying a new gaming keyboard online, the price shown is $\$40$ without taxes. If at checkout a $21\%$ sales tax is added, by how many dollars will the initial price increase?

Your cell phone indicates that it has $12\%$ of battery left. If the total capacity of the battery is $4500$ mAh (milliampere-hours), how many mAh of energy are left exactly in the device?

In a survey carried out in your 6th grade class, $18$ of the $30$ students have confirmed that they prefer horror movies to comedies. Calculate the percentage of students who prefer horror movies.

Hint: You can first write the ratio as a fraction $\frac{18}{30}$ and then find an equivalent fraction with a denominator of $100$.

The battery of Lucia's tablet has a total capacity of $5000$ mAh. If after playing "Roblox" for a while she has $18\%$ of battery left, how many mAh of energy does she still have left? What percentage of the battery has she already used?

A popular streamer has carried out a poll in his chat to decide which game to play today. Out of the $1200$ viewers who voted, $65\%$ chose "Minecraft" and the rest preferred "Among Us". How many people voted for "Among Us"?

In a sale at a sports store, some sneakers that cost $\$85$ have a $20\%$ discount. On the other hand, a hoodie that cost $\$60$ has a discount of $\$12$. Which of the two items has a greater percentage discount? Justify your answer by calculating the percentage for the hoodie.

To organize the end-of-year trip, the 6th grade students have sold raffle tickets. If they have already sold $360$ tickets, which represents $75\%$ of the total they had, how many tickets did they have to sell in total? How many do they still have left to sell?

An adventure video game takes up $12$ GB in a console's memory. If the system indicates that this game takes up $15\%$ of the total available memory, how many GB of capacity does the console's memory have in total?

In a multiple-choice math exam with $40$ questions, a student has answered $28$ questions correctly, missed $8$, and left $4$ blank. Calculate the percentage of correct answers, incorrect answers, and unanswered questions out of the total. Check that the sum of the three percentages is $100\%$.

The price of a laptop in a shop is $\$450$ excluding taxes. If a $21\%$ sales tax must be applied, what will be the final price we will have to pay for the laptop?

Emma has uploaded a video to TikTok. In the first two hours, she has gotten $180$ "likes". If she knows that $12\%$ of the people who watch the video give it a "like", how many views has the video had in total during those two hours?

In a trendy sneaker store, a model that costs $85 \text{ \$}$ has a $20\%$ discount. However, as it is the last day of the sale, they apply an additional discount of $10\%$ on the already reduced price. What is the final price of the sneakers? Is it the same as applying a single discount of $30\%$? Justify your answer by calculating both cases.

Alex has bought a computer to play his favorite video games. The final price he paid, including $21\%$ sales tax, was $1452 \text{ \$}$. His friend tells him that the computer cost $1200 \text{ \$}$ before taxes. Is his friend right? Carry out the necessary calculations to find the pre-tax price (without sales tax) of the computer.

In a survey carried out at your school about the use of social media, $45\%$ of the students prefer Instagram, $35\%$ prefer TikTok, and the remaining 48 students choose other platforms. How many students are there in total at the school? How many of them prefer Instagram?

A movie streaming service costs $9,99 \text{ \$}$ a month. If you decide to pay for the whole year at once, they offer you a $15\%$ discount. However, this month there is a special promotion and, on top of that already reduced annual price, they deduct a fixed $10 \text{ \$}$. How much will you save in total per year if you take advantage of both offers compared to paying month by month?

The storage of a cell phone is $128 \text{ GB}$. The operating system takes up $12,5\%$ of the total. If Alex has already filled $60\%$ of the remaining free space, how many gigabytes does he still have available to install new applications?

In a theater with a capacity for $850$ people, today $12\%$ of the tickets have remained unsold. Of the tickets sold, $65\%$ were for adults and the rest for children under 18. How many children under 18 have attended the theater today?

A soft drink brand has decided to reduce the sugar content of its flagship drink. Previously, a $330 \text{ fl oz}$ can contained $35 \text{ oz}$ of sugar. Now they have launched a version with a sugar reduction of $40\%$ and, in addition, they have increased the size of the can by $10\%$.

1. How many ounces of sugar does the new can have?

2. What percentage of sugar does the weight of the sugar represent over the total volume in the new can? (Consider $1 \text{ fl oz} = 1 \text{ oz}$ for the soft drink).

In the student council elections, candidate A obtained $30\%$ of the votes, candidate B obtained $25\%$, and candidate C received the rest of the votes. If candidate C won with 27 more votes than candidate B, how many students voted in total? How many votes did each candidate receive?