Question

A contractor under take to dig a canal 6 km long in 35 days and employed 90 men. He finds that after 20 days only 2 km of canal have been dug. How much more men must he employed to finish the work in time

Answer 1

so first we have to find the km dug per day per man
2km/20day=km per day =0.1
0.1/90=km per day per man = 0.001111111......
now find the kms per day he needs to dig
4km/15days=0.2666666......
divide this by the first value
0.2666666.../0.001111...
=240
240-90
=150
he needs 150 more men