Question

A contractor undertakes to dig a canal, 6 kilometers long, in 35 days and employed 90 men. He finds that after 20 days only 2 km of the canal has been completed. How many more men must be employed to finish the work on time?

Answer 1

Length of canal = 6 km

In 20 days canal made = 2 km

Remaining length of canal = 6 – 2 = 4 km

Remaining time = 35 – 20 = 15 days

In 20 days 2 km canal is made by = 90 men

In 1 day 2 km canal is made by = 90 x 20 men

In 15 days 2 km canal is made by = `(90xx20)/15` men

In 15 days 1 km canal is made by = `(90xx20)/(15xx2)` men

In 15 days 4 km canal is made by = `(90xx20xx4)/(15xx2)` men = 6 x 10 x 4 men = 240 men

Number of more men to be employed to finish the work in time = 240-90 = 150 men