Question

If 20 men working together can finish a job in 20 days, then find the number of days taken by 25 men of the same capacity to finish the job.

Answer 1

Hint: It is given that 20 men can finish a job in 20 days. Calculate the time required by 1 man to finish that job. The time required by one man to finish that particular job will be \[20\times 20\] . Then, calculate the time required by 25 men to finish that job by dividing the time taken by 1 man to finish that job, by 25 and then solve further.

Complete step-by-step answer:
According to the question it is given that the time required by 20 men to finish the job is 20 days.It is asked to find the number of days required by 25 men to finish that particular job.
Time required by 20 men to finish a job = 20 days.
So, the time required by 1 man to finish that particular job = \[20\times 20\] days.
Therefore, the time required by 25 men to finish that particular job = \[\dfrac{20\times 20}{25}\] .
On solving we get,
\[\begin{align}
  & =\dfrac{20\times 20}{25} \\
 & =16 \\
\end{align}\]
Hence, the time required to finish that job by 25 men is 16 days.

Note: In this question, while calculating the time required by 1 man to finish the job one might get it as \[\dfrac{20}{20}\] . If we do so, then we will get the time required to finish the job by 1 man less than the time required by 20 men to finish that job which is practically impossible. It should be written as \[20\times 20\] .