Question 531323
An apprentice carpenter can complete a job in 8 hours. After he has been working on the job for 1 hour, he is joined by a master carpenter and the two finish the job in 2 more hours. How long could it take the master carpenter alone to finish the entire job?
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x=hrs master carpenter alone can finish the entire job
1/x=his work rate
1/8 = work rate of apprentice
work done = work rate*hours worked
1/8*(1)+1/x*(2)=100% of job=1
1/8+2/x=1
2/x=1-1/8=7/8
7x=16
x=16/7 hrs
ans:
Master carpenter alone can finish the entire job in 16/7 hrs