Question

A house to be built in 80 days by a contractor. He hired 100 men for the work in beginning and 100 more after 70 days and completed the house on time. If contractor did not hire any extra men for the work, find the delay in the work.  

1. 12 dyas
2. 10 days
3. 15 days 
4. 16 days
5. 18 days

Answer 1

Correct Answer - Option 2 : 10 days

Given:

Days taken to built a house = 80 days

Men worked for first 70 days = 100 

Men worked after 70 days  = 200 

Formula Used:

Men₁ × Efficiency₁ × Days₁/Work₁ = Men2 × Efficiency2 × Days₂/Work2

Calculation:

After 70 days

The remaining work completed by 200 men in 10 days

⇒ 100 men will complete this work in

⇒ 200/100 × 10 = 20 days

⇒ The delay in work

⇒ (70 + 20) - 80 = 10 days

∴ If he didn't hire extra workers there will be delay of 10 days.