Answer:
The speed of the plane in still air is 154 mph.
Step-by-step explanation:
speed of plane in still air: v
speed of wind: a
speed of plane with wind: v + a
speed of planer against the wind: v - a
speed = distance/time
speed of plane against the wind:
v - a = (336 miles)/(2.4 hours)
v - a = 140
speed of plane with wind:
v + a = (336 miles)/(2 hours)
v + a = 168
We have a system of equations:
v - a = 140
v + a = 168
Add the equations to eliminate a:
2v = 308
v = 154
Answer: The speed of the plane in still air is 154 mph.
