SOLUTION: A job can be done by 25 men in 32 days. After 8 days, 5 men left. how long will it take the remaining men to finish the job?

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Question 885169: A job can be done by 25 men in 32 days. After 8 days, 5 men left. how long will it take the remaining men to finish the job?
Found 3 solutions by AnlytcPhil, richwmiller, MathTherapy:
Answer by AnlytcPhil(1806) About Me  (Show Source):
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A job can be done by 25 men in 32 days. After 8 days, 5 men left. how long will it take the remaining men to finish the job?
1 job can be done by 25 men in 32 days.

So when they had worked 8 days, they had done 1%2F4th of the job, since 8 is
1%2F4th of 32.

So that left 3%2F4 of the job for the 20 to do.

Also since a job can be done by 25 men in 32 days,

then 1 man would take 25 times as long or 800 days.

So each man's work rate is matrix%281%2C2%2C1%2Cjob%29%2Fmatrix%281%2C2%2C800%2Cdays%29 or
matrix%281%2C2%2C1%2F800%2Cjob%2Fday%29

20 men's work rate is 20 times the work rate of one man or 20 times
matrix%281%2C2%2C1%2F800%2Cjob%2Fday%29 or matrix%281%2C2%2C20%2F800%2Cjob%2Fday%29 which reduces to matrix%281%2C2%2C1%2F40%2Cjob%2Fday%29 

Suppose it took them N days to finish the job. Then 

matrix%281%2C2%2C1%2F40%2Cjob%2Fday%29%22%D7%22matrix%281%2C2%2CN%2Cdays%29 %22%22=%22%22matrix%281%2C2%2C3%2F4%2Cjob%29

expr%281%2F40%29N%22%22=%22%223%2F4

Multiply both sides by 40

10N = 30
  N = 3

It would take them 3 days.

Edwin

Answer by richwmiller(17219) About Me  (Show Source):
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25*32=800
it takes 800 man days to finish the job
8*25=200
in 8 days they used 200 man days
800-200=600
so they need 600 more man days to finish the job.
600/20=30 more days to finish the job
checking out reasonableness.
if the 25 continued they would take 24 more days so it is reasonable that it would take 20 men 30 days to finish

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

A job can be done by 25 men in 32 days. After 8 days, 5 men left. how long will it take the remaining men to finish the job?


It'll take the remaining 20 men, highlight_green%28highlight_green%2830%29%29 days to complete the remaining 3%2F4 of the job

You can do the check!! 



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