Correct Answer - Option 1 : 10
Calculation:
Had all workers participated on all days then they would have completed the work in 55% of the actual time or
in other words, it would have taken 55 man-days to complete the work.
Now, 1 man is withdrawn every day from the second day, so it took 100 man-days to complete the work.
100 man-days can have 10 men work for 10 days (As one man is withdrawn every day from the second day)
That is, On day 1, there were 10 men working
On day 2, there were 9 men working
On day 10, there was only one man working
Total number of man-days
⇒ 10 × (10 + 1)/2 = 55 man-days
This means the contractor had 10 men in his group.
If M1 men can do W1 in D1 by working H1 hours per day and M2 men can do W2 in D2 by working H2 hours per day then
⇒ M1D1H1/W1 = M2D2H2/W2
If A can do a piece of work in p days and B can do it in q days, Then A and B together can complete the same in
⇒ pq/(p + q)