Question 29092
The expert works at a rate of (1/6)job per hour.
The helper finishs (2/7)job in two hours, leaving (5/7)of the job to be done.
EQUATION:
Let x be the number of hours the expert has to work to finish the job.
Then (1/6)x=5/7
x=30/7 hrs. = 4 2/7 hrs= 60min. + (2/7)60 min.= 4 hr. 17 minutes.
Cheers,
stan H.