Leah flies 5200 miles in 11 hours What is the average speed

Leah flies 5,200 miles in 11 hours. What is the average speed of her airplane?

A. 472.73 miles/hour

B. 499.17 miles/hour

C. 512.33 miles/hour

D. 587.43 miles/hour

A. Set this up as a proportion.

5200 miles/11 hours = x miles/ 1 hour

Cross-multiply to get

11x=5200

X=472.73 miles per hour