20 men can do a piece of work in 24 days. After working for 6 days, additional men are employed to finish the work in 21 days from the beginning. Find the number of additional men

Answer 1

each man can do 1/(20*24) = 1/480 of the job in a day.

So, in 6 days, they have done 6*20/480 = 1/4 of the work.

So, if the new men work at the same speed, you need to do 3/4 of the job in 15 days.

m additional men can do 15m/480 = m/32 of the job in 15 days. So, we need

m/32 = 3/4
m = 24