Question

Ted can mow the lawn in 5 minutes by using his power mower. Galen takes 15 minutes to mow the same lawn using a push-type mower.
How many minutes would the job take if the two boys worked together?

Answer 1

Answer:

3.75 minutes.

Step-by-step explanation:

Let t represent the time taken by both to complete the work.

We have been given that Ted can mow the lawn in 5 minutes by using his power mower. So part of lawn mowed by Ted in one minute would be $\frac{t}{5}$.

We are also told that Galen takes 15 minutes to mow the same lawn using a push-type mower. So part of lawn mowed by Galen in one minute would be $\frac{t}{15}$.

Since both are mowing one lawn, so we can set an equation as:

$\frac{t}{5}+\frac{t}{15}=1$

$\frac{3t}{15}+\frac{t}{15}=1$

$\frac{3t+t}{15}=1$

$\frac{4t}{15}=1$

Cross multiply:

$4t=15$

$\frac{4t}{4}=\frac{15}{4}$

$t=3\frac{3}{4}$

$t=3.75$

Therefore, it will take 3.75 minutes for both to complete the job.