Ratios
What is a ratio? Give an example.
A ratio is a comparison of two quantities. Example: 2:1 (two to one).
What is a rate? Provide and example.
A rate is a ratio that compares two different kinds of quantities. Example: 60 miles per hour.
If 25% of a class of 20 students are girls, how many girls are there?
There are 5 girls. (Calculation: 0.25×20=5)
If 30% of a number is 15, what is the whole number?
The whole number is 50. (Calculation: 150/0.30=50)
What percent is 10 out of 50?
20%
If there are 3 apples and 2 oranges, what is the ratio of apples to oranges?
The ratio of apples to oranges is 3:2.
If you earn $60 for 4 hours of work, what is your hourly rate?
Your hourly rate is $15. (Calculation: 60/4=15)
If a shirt costs $40 and is on sale for 20% off, how much is the discount?
The discount is $8. (Calculation: 0.20×40=8)
If a student answered 18 questions correctly, which is 60% of the total questions, how many questions were there?
There are 30 questions. (Calculation: 18/0.60=30)
If you scored 80 out of 100 on a test, what percent did you earn?
You earned 80%.
A recipe calls for 4 cups of flour to 1 cup of sugar. What is the ratio of flour to sugar?
The ratio of flour to sugar is 4:1.
A car travels 240 miles in 3 hours. What is the rate of speed in miles per hour?
The rate of speed is 80 miles per hour. (Calculation: 240miles/3hours=80miles/hour)
If you scored 90% on a test with 50 questions, how many questions did you get correct?
You got 45 questions correct. (Calculation: 0.90×50=45)
If 40% of a class of 25 students is absent, how many students are present?
There are 15 students present.
(Calculation: 25−0.40×25=15)
If a product originally costs $50 and is now $40, what is the percent decrease?
The percent decrease is 20%.
(Calculation: 50−40//50×100=20%)
If the ratio of boys to girls in a class is 2:3 and there are 12 boys, how many girls are there?
If the ratio is 2:3 and there are 12 boys, then there are 18 girls. (Calculation: 12 boys/2 ×3=18 girls)
If you can read 30 pages in 1 hour, how many pages can you read in 4 hours?
You can read 120 pages in 4 hours. (Calculation: 30pages/hour×4hours=120pages)
A store has a sale where 30% of the items are discounted. If there are 80 items, how many are discounted?
There are 24 items discounted.
(Calculation: 0.30×80=24)
If you have $45 and that represents 75% of your savings, how much do you have in total?
You have $60 in total. (Calculation: 45/0.75=60)
A student reads 15 out of 20 books in a month. What percent of the books did the student read?
The student read 75% of the books.
(Calculation: 15/20×100=75%)
If a car travels 150 miles using 5 gallons of gas, what is the ratio of miles per gallon?
The ratio of miles per gallon is 30 miles per gallon. (Calculation: 150miles/5gallons=30miles/gallon)
A recipe requires 2 tablespoons of sugar for every 5 cups of water. What is the rate of sugar to water?
The rate of sugar to water is 2/5 tablespoons of sugar per cup of water.
If you have a total of $200 and spend 15%, how much money do you have left?
You have $170 left.
(Calculation: 200−0.15×200=170)
If 20% of a number is 8, what is the whole number?
The whole number is 40. (Calculation: 8/0.20=40)
If 12 out of 30 students prefer chocolate ice cream, what percent prefer chocolate?
40% prefer chocolate.
(Calculation: 12/30×100=40%)