Question

7. If 30 men can do a piece of work in 27 days. In how
many days can 18 men do another piece of work 3
times as great ?
(A) 45 days
(BS 135 days
(C) 100 days
(D) 125 days​

Answer 1

Another approach is by the unitary method, which is simpler to understand.

Let the amount of work being done by 30 men in 27 days be x.

Then the amount of work done by 30 men in 1 day is x/27.

The amount of work done by 1 man in 1 day will be (x/27) /30 = x/(27*30)

The amount of work done by 18 men in 1 day will be, (x/(27*30)) *18

So now we know how much work 18 men can do in a single day.

The amount of work to be done by these 18 men is thrice of the previous work, I.e. It is 3x.

Thus, the no. Of days required = total amount of work/work done per day

=3x/(x*18/27*30)=135 days

Here you basically Try to find how much work is done by one person in one day, and using that you find how much work 18 men will do in one day, which leads you to the final answer.

Answer 2

Answer:

135 days...

Step-by-step explanation:

if 30 men can do work in 27 days..

then, 1 man can do this work= 30×27 days

and 18 men could do this work...

:: 30×27÷18 = 45 days

and another piece of work 3

could be done in 45×3 = 135 days.

so, 135 days is an answer..