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Practice Solving Percent Word Problems

Site: Saylor Academy
Course: MA007: Algebra
Book: Practice Solving Percent Word Problems
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Date: Tuesday, 15 July 2025, 7:41 AM

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Table of contents

Practice Problems

  1. Mrs. Conley asks her class what kind of party they want to have to celebrate their excellent behavior. Out of all the students in the class, 5 want an ice cream party, 7 want a movie party, 10 want a costume party, and the rest are undecided.

    If 20% want an ice cream party, how many students are in the class?

  2. Emily's family loves to work together in the garden. They have a slight preference for flowers, as ‍60% of their plants are flowers and ‍40% are vegetables. They have ‍50 plants growing in the garden.

    How many vegetable plants do they have?

  3. 2%‍ of the students at Hamilton Middle School have red hair. There are ‍700 students at Hamilton Middle School.

    How many students at Hamilton Middle School have red hair?

  4. A coin contains 9 grams of nickel and 16 grams of copper, for a total weight of 25 grams.

    What percentage of the metal in the coin is copper?

  5. When a grizzly bear hibernates, its heart rate drops to 10 beats per minute, which is 20% of its normal value.

    What is a grizzly bear's normal heart rate when not hibernating?

  6. Elmer has a collection of ‍300 fossils. Of these, 21% are fossilized snail shells.

    How many fossilized snail shells does Elmer have?

  7. An estimated ‍3 out of every ‍25 men are left-handed.

    What percent of men are left-handed?

Source: Khan Academy, https://www.khanacademy.org/math/cc-sixth-grade-math/x0267d782:cc-6th-rates-and-percentages/cc-6th-percent-word-problems/e/percentage_word_problems_1
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Answers

  1. We know the 5 students that want an ice cream party equal 20% of the class. We need to find out the total number of students in the class (100%).

    q1-answer

    Since we know that 5 students equal 20% of the class, we can multiply by 5 to see how many students equal 100%.

    Percent 20% \(\stackrel{\times 5}\rightarrow\) 100%
    Students
    		 5 \(\stackrel{\times 5}\rightarrow\) 25

    There are 25 students in the class.

  2. We know that the whole garden‍ (100%) has ‍50 plants. We need to find out how many are vegetables, which are ‍40% of the garden.

    q2-answer

    Because the ‍50 total plants cover all ‍5 of the ‍20% partitions, we first divide ‍50 plants by ‍5 to see that each ‍20% equals ‍10 plants.

    q2-answer

    We then multiply the ‍10 plants by ‍2 to see how many plants equal ‍40%.

    Percent 100% \(\stackrel{\div 5}\rightarrow\) 20% \(\stackrel{\times 2}\rightarrow\) 40%
    Plants 50 \(\stackrel{\div 5}\rightarrow\) 10 \(\stackrel{\times 2}\rightarrow\) 20

    There are ‍20 vegetable plants in the garden.

  3. We know that the entire population of the school ‍(100%) is equal to ‍700 people. We need to find out how many people equal ‍2% of the students.

    We can first divide the population by ‍100 to see how many people equal ‍1% of the students, then multiply by ‍2 to see how many people equal ‍2% of the students.

    Percent 100% \(\stackrel{\div 100}\rightarrow\) 1% \(\stackrel{\times 2}\rightarrow\) 2%
    Students
    		 700 \(\stackrel{\div 100}\rightarrow\) 7 \(\stackrel{\times 2}\rightarrow\) 14

    There are ‍14 students at Hamilton Middle School with red hair.

  4. We know that an entire coin (100%) weighs 25 grams.

    Grams 25 \(\stackrel{\div 25}\rightarrow\) 1 \(\stackrel{\times 16}\rightarrow\) 16
    Percent
    		 100% \(\stackrel{\div 25}\rightarrow\) 4% \(\stackrel{\times 16}\rightarrow\) 64%


    The table shows that we can divide by 25 to figure out that 4% of the coin is represented by 1 gram.

    We know that the coin has 16 grams of copper, so we multiply 4% by 16 to find the percent of the coin represented by the 16 grams of copper.

    64% of the metal in the coin is copper.

  5. We know that the rate of 10 beats per minute is equal to 20% of the normal rate. We need to find out the normal (100%) number of beats per minute a grizzly bear has when not hibernating.

    q5-answer

    Since we already know the value for 20%, we can just multiply by 5 to see how many heart beats equal 100%.

    Percent 20% \(\stackrel{\times 5}\rightarrow\) 100%
    Heart beats
    		 10 \(\stackrel{\times 5}\rightarrow\) 50


    The grizzly bear's usual heart rate is ‍50 beats per minute.

  6. We know that the total number of fossils ‍(100%) is ‍300. We need to find out how many are fossilized snail shells, which are ‍21% of the total.

    We can first divide by ‍100 to see how many fossils ‍1% would be, then multiply by ‍21 to see how many fossilized snail shells 21% equals.

    Percent 100% \(\stackrel{\div 100}\rightarrow\) 1% \(\stackrel{\times 21}\rightarrow\) 21%
    Fossils
    		 300 \(\stackrel{\div 100}\rightarrow\) 3 \(\stackrel{\times 21}\rightarrow\) 63


    There are ‍63 fossilized snail shells in Elmer's collection.

  7. We can think of a group of ‍25 men as the entire amount ‍(100%). We need to find out what percentage of that amount ‍3 men makes.

    Men 25 \(\stackrel{\div 25}\rightarrow\) 1 \(\stackrel{\times 3}\rightarrow\) 3
    Percent
    		 100% \(\stackrel{\div 25}\rightarrow\) 4% \(\stackrel{\times 3}\rightarrow\) 12%

    The table shows that we can divide by ‍25 to find what percentage of the group ‍1 man is.

    Then we multiply by ‍3 to get from ‍1 man to ‍3 men, the number that are left-handed.

    ‍12% of men are left-handed.