Answer:
John and Shawn spent the same number of hours after [tex]4[/tex] weeks.
Step-by-step explanation:
Number of hours already completed by John to his volunteer project [tex]=40[/tex] hours
Number of hours spent by John each week to his volunteer project [tex]=5[/tex] hours
Number of hours spent by Shawn each week to his volunteer project [tex]=15[/tex] hours
Suppose John and Shawn spent the same number of hours after [tex]x[/tex] weeks.
Therefore,
[tex]40+5x=15x[/tex]
[tex]40=15x-5x\\40=10x[/tex]
[tex]x=4[/tex] weeks.
So,
John and Shawn spent the same number of hours after [tex]4[/tex] weeks.