Question

Steve and Hillary can mow the lawn in 60 minutes if they work together. If Hillary works three times as fast as Steve, how long does it take for Steve to mow the lawn alone

Answer 1

Answer:

Steve can mow the lawn in 240 minutes

Explanation:

It is given Hillary works three times as fast as Steve

When both work together the work is completed in 60 minutes

Let Steve can do 1 work in 1 minute

So Hillary can do 3 work in 1 minute

So work done by both in 1 minute = 1+3 = 4

As they can complete the work in 60 minutes

So total work = 4×60 = 240 work

As Steve can do 1 work in a minute

So time taken by Steve to complete the work $=\frac{240}{1}=240minutes$

Answer 2

Answer:

Steve will take 240 minutes or 4 hours.

Explanation:

Steve and Hillary can mow a lawn in 60 minutes by working together. However, Hillary works three times faster than Steve.

Let's assume Steve takes takes x minutes to mow alone.

This implies that Hillary can mow alone in x/3 minutes.

In a minute, Steve can mow 1/x of the lawn, so this means Hillary can mow 3/x of the lawn.

In a minute together then can mow,

= $\frac{1}{x} + \frac{3}{x}$

= $\frac{4}{x}$

In 60 minutes they can mow

= $\frac{4}{x} \times 60$

= $\frac{240}{x}$

This means that it takes 4 hours for Steve to mow the lawn alone.