Given :
A group of men decided to do a job in 8 days.
10 men dropped out every day, the job got completed at the end of the 12th day.
To Find :
How many men were at the beginning ?
Solution :
Let, total number of men initially are n.
It none of them leave, total work :
W = 8n ...1)
It is given that 10 men are dropped each day it takes them 12 day to complete the work :
W = ( n ) + ( n - 10 ) + ( n - 20 ) + .... + ( n - 110 )
W = 12n - ( 0 + 10 + 20 + ...... + 110 )
W = 12n - 660 ...2)
Since, total work is same in both the cases, so equating both equation, we get :
12n - 660 = 8n
4n = 660
n = 165
Therefore, their are 165 men in the beginning.
