Question 16.

Let the unit of work done by 1 man in 1 hour and 1 day be $1$ MDH unit (Man Day Hour).

Thus, in 7 hours per day for 10 days, the work done by $N$ people =

$N \times 7 \times 10$ MDH units.

Since this is equal to 35% of the total work,

35% of the total work = $N \times 7 \times 10$ MDH units.

Total work = $\dfrac{(N \times 100 \times 7 \times 10)}{35} = 200N$ MDH units.

The work left = $200N - 70N = 130N$ MDH units.

Now, 10 people left the job. So, the number of people left = $(N - 10)$

Since $(N - 10)$ people completed the rest of work in 14 days by working 10 hours a day,

(N−10)×14×10=130N

$10N = 1400$

$N = 140$