Question

Ava and Kelly ran a road race, starting from the same place at the same time. Ava ran at an average speed of 6 miles per hour. Kelly ran at an average speed of 8 miles per hour.
When will Ava and Kelly be 3/4 mile apart?

Answer 1

Answer:

So what the other guy said in minutes was 22.5 minutes

Step-by-step explanation:

Answer 2

Hello!

The answer is:

It will took 0.375 hours for Ava and Kelly to be 3/4 miles apart.

Why?

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,

$v_{Ava}=6mph$

Then, writing the equation,

$x_{Ava}=x_{o}+v_{Ava}*t$

$x_{Ava}=x_{o}+v_{6mph}*t$

Calculations for Kelly:

We have the following information,

$v_{Kelly}=8mph$

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,

$x_{Ava}+0.75miles=x_{o}+v_{Kelly}*t$

$x_{Ava}+0.75miles=x_{o}+v_{8mph}*t$

Now, substituting Ava's speed into the second equation, we have:

$x_{o}+6mph*t+0.75miles=x_{o}+8mph*t$

$6mph*t+0.75miles=+8mph*t$

$8mph*t-6mph*t=0.75miles$

$2mph*t=0.75miles$

$t=\frac{0.75miles}{2mph}=0.375hours$

Hence, we have that it will took 0.375 hours for Ava and Kelly to be 3/4 miles apart.

Have a nice day!