Hours Question

Question

If it takes 6 hours for 2 people to clean a house, how many hours will it take 4 people, working at the sae rate, to clean another house that is the same size?

 

a. 2/3

b. 1 1/2

c. 2

d. 3

Answer 1

In this problem the number of people and the number of hours required to finish a job are inversely proportional:

 

t = K / p       where t=time in hours,  p=number of people and K= constant of proportionality

 

Use the information they gave you in the problem: 2 people => 6 hours

 

6 = K / 2 therefore K=12

 

Use the information they gave you in the problem and the value of K you obtained above: 4 people => x hours

 

x = 12 / 4 = 3  which means by doubling the number of people the time it takes to finish the job is half the time.

 

 

Answer 2

Mai Kou, it should take double the people half the time, so your answer is d.