Question

Tonya runs 8 kilometers in 60 minutes. at this rate, how long would it take her to run 2 kilometers?

Answer 1

we know that

Tonya runs $8$ kilometers in $60$ minutes

so

by proportion

Find the time take Tonya to run  $2$ kilometers

$\frac{60}{8}\frac{minutes}{km}=\frac{x}{2}\frac{minutes}{km} \\ \\x*8=60*2\\ \\x=60*2/8\\ \\x=15\ minutes$

therefore

the answer is

$15\ minutes$

Answer 2

Here they have told you the extended amount of time and what that would give you. 8 kilometers=60 minutes, yes?
This is a ratio, meaning that you can have mulitiple numbers that mean the same thing.
You would, instead of multiplying like you would for a number larger than you're looking for, would simply divide both sides by the same number so that they'll stay even and balanced, the values unchanged.
So 8 and 60 have a same multiple, 4.
Divide four on both sides to get 2 and 15.
2 would be the number of kilometers you are looking for and 15 would be the number of minutes that Tonya would need to run.