Question

Two bricklayers, Sam and Joe, are working on your house. Sam can complete the work in 5 hours, while Joe can complete the work in 3 hours. How many hours does the bricklaying take if they work together?

A. 15/8
B. 15/9
C. 6/8
D. 4/3

Answer 1

3x+5x=15
8x=15
x=15/8 

You need to add the two rates together, like I've shown above. Hope this helped!

Answer 2

Answer:  The correct option is (A) $\dfrac{15}{8}~\textup{hours}.$

Step-by-step explanation:  Given that Sam can complete the work in 5 hours, while Joe can complete the work in 3 hours.

We are to find the number of hours they will take to complete the work if they work together.

We have

Sam can complete the work in 5 hours.

So, in 1 hour, the portion of the work Sam can complete $\dfrac{1}{5}.$

Joe can complete the work in 3 hours.

So, in 1 hour, the portion of the work Joe can complete $\dfrac{1}{3}.$

Therefore, if they work together, the portion of the work they will complete in 1 hour will be

$\dfrac{1}{5}+\dfrac{1}{3}=\dfrac{3+5}{15}=\dfrac{8}{15}.$

Thus, they can complete the work in $\dfrac{15}{8}~\textup{hours}.$

Option (A) is correct.