Against the wind a small plane flew 175 miles in 1 hour and 10 minutes. The return trip took only 50 minutes.?
Update:
Against the wind a small plane flew 175 miles in 1 hour and 10 minutes. The return trip took only 50 minutes. What was the speed of the wind? What was the speed of the plane in still air?
Answers & Comments
Against the wind a small plane flew 175 miles in 1 hour and 10 minutes.
The return trip took only 50 minutes.
What was the speed of the wind?
What was the speed of the plane in still air?
x = rate of the wind
v = speed of the small plane in still air
1 hour and 10 min = 1 10/60 hours = 7/6 hours
the speed of the plane against the wind is v - x = 175 / (7/6) miles per hour
the return trip flying in the direction of the wind with speed v + x took 50 min = 50/60 = 5/6 hours
thus we can write
v - x = 175 / (7/6) = 150
v + x = 175 / (5/6) = 210
by solving the system of equations
v = 180 mph
x = 30 mph
The speed of the plane in still air is 180 mph.
The speed of the wind is 30 mph.
Let s be the speed of the plane in still air.
Let w be the speed of the wind.
Against the wind, the net speed will be s-w.
With the wind, the net speed will be s+w.
Against the wind --> 70 minutes or 7/6 hours
With the wind --> 50 minutes or 5/6 hours
Equation against the wind:
175 = 7/6 * (s-w)
6/7 * 175 = s - w
150 = s - w
Equation with the wind:
175 = 5/6 * (s+w)
6/5 * 175 = s + w
210 = s + w
Add the last two equations to eliminate w:
360 = 2s
s = 180
210 = 180 + w
w = 30
Answer:
The plane travels at 180 mph (in still air) and the wind is blowing at 30 mph.
w = speed of wind
s = speed in still air
50 min = 5/6 hr and 1 hr 110 min = 7/6 hr. Distance = time times speed so
175 = 7/6 (s - w)
175 = 5/6 (s + w)
Multiply row 1 by 6/7 and row 2 by 6/5 to get rid of the fractions
150 = s - w
210 = s + w and now add the two together to eliminate w
360 = 2s so solve for s then plug in to get w