Question

It take Mr. Branches 5 hours to rake the leaves. If his son joins him in the work, they can rake the leaves in 3 hours. How long would it take Mr. Branches's son to rake the leaves on his own? 3 3/4 hours 6 hours 7 1/2 hours

Answer 1

Answer: 7 1/2 hours =x

Explanation:

Hi, to answer this question we have to express the information in ratios.

Mr. Branche's time per job : 1job /5hours

MR Branches’ son = 1 job /x hours

Both = 1job/3 hours

If we add, r branches and his son's work, we obtain the total spent time by both of them.

1/5 + 1/x = 1/3

Solving for x:

1/x = 1/3 -1/5

1/x = 2/15

1 ( 2/15) =x

7 1/2 hours =x

Answer 2

Answer: 7
`(1)/(2)` hours

Explanation:

Dad:
`(1)/(5)`

Son:
`(1)/(x)`

Together:
`(1)/(5)` +
`(1)/(x)` =
`(1)/(3)`

`(1)/(5)`(15x) +
`(1)/(x)`(15x) =
`(1)/(3)`(15x)

3x + 15 = 5x

-3x -3x

15 = 2x

÷2 ÷2

7.5 = x