Proportion Homework

Bernie got 16 out of 40 math problems correct on his test. What percent did he get correct?

(a)  

Answer explanation

$\frac{16}{40}=\frac{x}{100}$
Simplify to ... $\frac{8}{20}=\frac{16}{40}=\frac{x}{100}$
20 times 5 is 100, so 8 times 5 is 40%

If a 30-foot tree casts a shadow 18 feet long, then a 20-foot tree will cast how long of a shadow?

(a)  

Answer explanation

$\frac{30}{18}=\frac{20}{x}$
Simplify to ... $\frac{10}{6}=\frac{30}{18}=\frac{20}{x}$
10 times 2 is 20, so 6 times 2 is 12.

Tags

CCSS.7.RP.A.3

Out of all the girls that Charles has dated, 18 of them have broken up with him, which is 72%. How many girls has Charles dated?

(a)  

Answer explanation

$\frac{18}{x}=\frac{72}{100}$
Simplify to ... $\frac{18}{x}=\frac{72}{100}=\frac{36}{50}$
36 divide by 2 is 18, so 50 divided by 2 is 25.

Tags

CCSS.6.RP.A.3C

Alan can type 80 words in two minutes. How many words can he type in an hour?

(a)  

Answer explanation

$\frac{80}{2}=\frac{x}{60}$
2 times 30 is 60, so 80 times 30 is 2400.

Tags

CCSS.6.RP.A.3B

The Cowboys have lost 6 games and won 4. What percent of their games have they lost?

(a)  

Answer explanation

$\frac{6}{\frac{4}{10}}=\frac{x}{\ \frac{ }{100}}$
10 times 10 is 100, so 6 times 10 is 60.

Dogs out number cats in an area by a ratio of 9 to 8. There are 180 dogs in the area. How many cats are there?

(a)  

Answer explanation

$\frac{9}{8}=\frac{180}{x}$
9 times 20 is 180, so 8 times 20 is 160.

Eric earned 48 points on his last test. If there were 60 possible points, what was his percent grade?

(a)  

Answer explanation

$\frac{48}{60}=\frac{x}{100}$
Simplify to ... $\frac{4}{5}=\frac{12}{15}=\frac{24}{30}=\frac{48}{60}=\frac{x}{100}$
5 times 20 is 100, so 4 times 20 is 80.

Lindsey’s car gets 27 miles per gallon of gas. How many miles will the car travel on 12 gallons of gas?

(a)  

Answer explanation

$\frac{27}{1}=\frac{x}{12}$
1 times 12 is 12, so 27 times 12 is 324.

Tags

CCSS.7.EE.B.3

There are 150 calories in 12 ounces of Dr. Pepper. How many calories are in 8 ounces of Dr. Pepper?

(a)  

Answer explanation

$\frac{150}{12}=\frac{x}{8}$
Simplify to ... $\frac{25}{2}=\frac{75}{6}=\frac{150}{12}=\frac{x}{8}$
2 times 4 is 8, so 25 times 4 is 100.

Tags

CCSS.6.RP.A.3B

Bill is in a class of 15 boys and 35 girls. 40% of the students in the class take the bus to school. How many students do not take the bus to school?

(a)  

Answer explanation

$\frac{x}{\ \frac{ }{50}}=\frac{60}{\frac{40}{100}}$
100 divided by 2 is 50, so 60 divided by 2 is 30.

Tags

CCSS.6.RP.A.3C