Question

The amount Troy charges to mow a lawn is proportional to the time it takes him to mow the lawn. Troy charges $30 to mow a lawn that took him 1.5 hours to mow. Which equation models the amount in D dollars Troy charges when it takes him H hours to mow a lawn.

Answer 1

D = 20H

Explanation:

The amount Troy (D, in dollars) charges to mow a lawn is proportional to the time (H, in hours) it takes him to mow the lawn.

Hence, we can write D = kH ......... (1), where k is a constant.

Now, given that Troy charges $30 to mow a lawn that took him 1.5 hours to mow.

So, from equation (1) we get

30 = 1.5k

⇒ k = 20.

Therefore, equation (1) becomes D = 20H (Answer)