Answer: 4 miles per hour.
Step-by-step explanation:
Total distance ran by Joy= 13 miles
Total time taken by Joy =3 and 1/4 hours
\(=3+\frac{1}{4}\ hours\\=\frac{13}{4}\ hours\)
The average rate of running= \(\frac{\text{total distance}}{\text{time taken}}\)
\(\frac{13}{\frac{13}{4}}=\frac{4}{1}=4\text{ miles per hour}\)
Hence, her average rate=4 miles per hour.
