Question 808432
You have the hours backwards.
Jerry worked 3 hours and Ben 2 hours
Ben showed up late after Jerry had started
Ben worked for 2 hours at the rate of 1/8 each hour
2/8=1/4
so Ben did 1/4 of the job in 2 hours and Jerry did 3/4 of the job in 3 hours.
He did 1/4 of the job each hour

2/j+2/b=1-1/j
3/j+2/8=1
3/j=3/4
j=4 hours alone