1)

A contractor undertakes to do a piece of work in 40 days. He engages 100 men at the beginning and 100 more after 35 days and completes the work in stipulated time. If he had not engaged the additional men, how many days behind schedule would it be finished ?

A) 5

B) 6

C) 7

D) 8

$[(100\times 35)+(200\times 5)]$ men can finish the work in $1$ day.
$\therefore 4500$ men can finish the work in 1 day.
$100$ men can finish it in $\frac{4500}{100}$ = 45 days.