Problema Solution
Flying with the wind, a plane flew 1,120 mi in 4 h. Against the wind, the plane required 7 h to fly the same distance. Find the rate of the plane in calm air and the rate of the wind
Answer provided by our tutors
Let
w = the rate of the wind, w>0
v = the rate of the plane in calm air, v>0
d = 1,120 mi
t1 = 4 h
t2 = 7 h
since distance = speed*time we have
Flying with the wind the speed of the plane is: v + w
v + w = 1120/4
Flying against the wind the speed of the plane is: v - w
v - w = 1120/7
by solving the system of equations:
v + w = 1120/4
v - w = 1120/7
........
........
v = 220 mph
w = 60 mph
The rate of the plane in calm air is 220 mph.
The rate of the wind is 60 mph.