Hey there! The answer is 1 1/8 mile.
To find the amount of miles Sarah ran, we need to multipy the length of the track by the times she run that distance.
[tex]1 \frac{1}{2} \times \frac{3}{4} = \frac{3}{2} \times \frac{3}{4} = \frac{9}{8} = 1 \frac{1}{8} [/tex]
Rembember: multiplying a fraction means you have to multiply the numerator by the numerator (of the other fraction) and the denominator by the denominator (of the other fraction)
The answer is 1 1/8 mile.
~ Hope this helps you!