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

So what the other guy said in minutes was 22.5 minutes

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=(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!