Question

4 people can dig a hole in 3 hours. How long does it take 9 people.

Answer 1

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

Explanation:

Answer 2

Answer: 1 hour 20 minutes

Explanation:

Let's figure out how long it would take 1 person to dig the hole and then divide that number by 9 (since they are sharing the workload).

`(1)/(4)x=3\qquad \implies \qquad x = 12\quad \text{It takes 12 hours for 1 person}\\\\\\\frac{12\ \text{(for 1 person)}}{9\ \text{(people)}}\quad =1(1)/(3)\quad =\large\boxed{1\ hour\ 20\ minutes}`