Description for Correct answer:
3 men = 6 boys

= 1 man = 2 boys

Therefore, 4 man + r boys = 4 mean + 2 men = 6 men

Therefore, 3 men can do a work in 18 days.

Therefore, 1 man can do a work in 18 X 3 days.

Therefore, 6 men can do the work in \( \Large \frac{18 \times 3}{6} \) days

Therefore, Required number of days = \( \Large \frac{2000 \times 20}{25} \) = 9 days