Solve the Problem. -A Helicopter Flies 168 Miles Against the Wind in 2

Multiple Choice

Solve the problem.
-A helicopter flies 168 miles against the wind in 2 hours; with the wind, it can fly 252 miles in the same amount of time. Find the speed of the helicopter in still air.

A) 21 miles per hour
B) 63 miles per hour
C) 105 miles per hour
D) 84 miles per hour