<h2>Hello!</h2>
The answer is:
It will took 0.375 hours for Ava and Kelly to be 3/4 miles apart.
<h2>Why?</h2>To calculate how long after they start they will be 3/4 miles apart, we need to write two equations.
So, writing the equations, we have:
Calculations for Ava:
We have the following information,
Then, writing the equation,
Calculations for Kelly:
We have the following information,
We need to calculate when Kelly will be 3/4 miles apart of Ava, so, it's position will be the Ava's position plus 3/4 miles.
Then, writing the equation,
Now, substituting Ava's speed into the second equation, we have:
Hence, we have that it will took 0.375 hours for Ava and Kelly to be 3/4 miles apart.
Have a nice day!