4 people can dig up a trench in 3 hours. How long will it take 9 people?

Question

Please give the answer in mins

Answer 1

t represents the amount of time

4 : 3 :: 9 : t  proportion

4t = (3)(9)   product means/extremes

 

Can you solve for t and answer?

Answer 2

9 people is 9/4 = 2.25 times more people than 4 people. So, they can do it faster. 3 hours/2.25 = 1.33 hours 1.33 hours x 60 minutes/hour = 80 minutes