If 25 men can build a wall 70 meters long in 6 days, what length of a similar wall can be built by 35 men in 3 days?

Question: If 25 men can build a wall 70 meters long in 6 days, what length of a similar wall can be built by 35 men in 3 days?

Solution:
In 6 days 25 men can build 70 meters
∴ In 1 day 1 man can build 70/(6 × 25) meters.
∴ In 3 days 35 men can build (70 × 35 × 3)/(6 × 25) meters.
= 49 meters.