An airplane flew 3.5 hours with a 60 mph head wind. The return trip with a tail wind of the same speed took 2.5 hours. Find the speed of the plane in still air.

Question

anonymous · Answer

d_1 = 3.5(x - 60)
d_2 = 2.5(x + 60
d_1 = d_2
3.5(x - 60) = 2.5(x + 60)
3.5x - 210 = 2.5x + 150
x = 360
The speed in still air is 360 mph.
These questions often involve the formula s = d/t. You just have to manipulate the formula to change it.
s = d/t
d = st
t = d/s