9 men do work in 10 days=10*9=90 unit work left=180 unit work to be done in one day=180/2=90 unit additional men=90-9=81
90 men are required per day
10 * 3 = 30 days; 30 - 10 = 20 days it would take to do the job of nine men. 9 * 20 = 180 man-days; 180/2 = 90 men; 90 - 9 = 81 men additional men required to finish the remaining work in 2 more days.
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
10 men and 15 women complete half of the work in 12 days and 6 men and 15 women complete one third of the work in 10 days. How many days are required to complete the same full work by taking 10 men and 30 women?
If 9 boy working 15/2 hours a day can finish a work in 20 days, then how many days will be taken by 12 boy working 6 hours a day to finish the work, it being given than 3 boy of latter type work as much as 2 boy of he former type in the same.
A certain number of men can finish a piece of work in 30 days. If however there were 15 men less it will take 30 days more for the work to be finished. How many men were there originally?