6 men do a piece of work in 10 days with an effort of 6 hrs/day. How many extra men are required to do the double work..

Question

Six men do a piece of work in 10 days with an effort of 6 hours per day. How many extra men are required for doing the work of double strength in 4 days with an effort of 5 hours per day

Answer 1

To solve this we should focus on the fact that here the speed with which each person works is constant throughout.
Also it's convenient if we know ( work = work speed × time )

Speed of 6 men = ( 1 work / ( 6(hrs/day)×10 days )) = (1/60)
Speed of 1 man = 1/360

Speed of X men = ( 2 work / ( 5(hrs/day)× 4 days )) = 1/10
Speed of 1 man = 1/(10*X) = 1 / 360
Therefore X = 36 men which is 30 more men from the first case

So we need 30 more men to complete double the work in shorter time frame of 20 hrs vs 60 hrs.

Answer 2

10days required to complete double the work. j janardhana setty