Question

If 20 men can do a piece of work in 72 days, then
how many more men are needed to complete the
same piece of work in 30 days?​

Answer 1

Given 20 men does a piece of work -> 72 days

   Let Y men do same work in -> 30 days

So we get the relations

                  20 men -> 72 days

                  Now 1 man takes $\frac{72}{20}$ days = 3.6 days

So 1 man takes 3.6 days

    Y men takes 30 days

   1 man -> 3.6

  Y men -> 30 days

 3.6 Y = 30 x 1

   Y = 30/3.6 = 300/36 = 8.33

    approx 8 men

Thus 8 more men are required to complete the same peice of work in 30 days