Question

John and Shawn are racing to see who can get his community service hours for scouting completed first. John, who has already completed 40 hours, plans to volunteer for 5 hours per week going forward. Shawn hasn't started yet, but plans to dedicate 15 hours per week to his volunteer project from now on. Before too long, the boys will be tied, with the same number of volunteer hours. How long will that take?

Answer 1

John and Shawn spent the same number of hours after
`4` weeks.

Explanation:

Number of hours already completed by John to his volunteer project
`=40` hours

Number of hours spent by John each week to his volunteer project
`=5` hours

Number of hours spent by Shawn each week to his volunteer project
`=15` hours

Suppose John and Shawn spent the same number of hours after
`x` weeks.

Therefore,

`40+5x=15x`

`40=15x-5x\\40=10x`

`x=4` weeks.

So,

John and Shawn spent the same number of hours after
`4` weeks.