How many workers will be needed to complete a task in 3 days, given that it takes 12 days for 5 workers to complete the same task?

Question

First convert to an equation, to then multiply as well as turn into a proportion to solve the given problem

Answer 1

3  days ------------> x workers ;

 

12 days------------> 5 workers ;

 

12/3 = x/5 ⇔ 4 = x/5 ⇒ x = 20 workers. More workers reduce the duration for completing the same task.

 

Divide the number of days by 4; multiply the number of workers by 4.

Answer 2

This is an inverse relation - as one value increases the other value decreases.

More workers ⇒ less days, more days ⇒ less workers

 

The job takes 60 worker-days (12 · 5)

So 60 worker-days / 3 workers = 20 days.

 

Or

 

3 is one-fourth of 12 days.

4 times as many workers are need - 20