SOLUTION: Twenty laborers could finish a certain construction job in 35 days. After 11 days, five laborers quit the work and are not replaced until 4 days. How many more laborers should be a

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Question 5865: Twenty laborers could finish a certain construction job in 35 days. After 11 days, five laborers quit the work and are not replaced until 4 days. How many more laborers should be added to complete the job on time?
Answer by Abbey(339) About Me  (Show Source):
You can put this solution on YOUR website!
This is easiest if we define how much work each laborer can perform in a day:
20 laborers can do the entire job in 35 days, so each day 20 workers can perform 1%2F35 of the job
each person can perform 1%2F20+of+the+daily+work%2C+or+%281%2F35%29%2A%281%2F20%29=%281%2F700%29
after 11 days:
11%2A20%2A1%2F700+=+220%2F700
4 days later:
4%2A16%2A1%2F700+=+64%2F700
There is now 285%2F700 work complete, leaving 415%2F700 work.
If we divide 415/700 by 20, it will give us the amount of work each day that must be completed: 20.75%2F700
so they must hire an additional 5 people (20.75-16 = 4.75, then round up)to finish the job.
check by the amount of work performed:
16 people * 35 days * 1/700 = 560/700
4 people * 11 days * 1/700 = 44/700
5 people * 20 days * 1/700 = 100/700
560%2F700+%2B+44%2F700+%2B+100%2F700+=+704%2F700