Answer: 250
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Explanation:
x = speed of the plane in mph
x-180 = speed of the car, since its 180 mph slower than the plane
For the plane, we can form the equation
distance = rate*time
d = r*t
500 = xt
t = 500/x
For the car, we can say,
d = rt
140 = (x-180)t
140 = (x-180)*(500/x)
140x = 500(x-180)
140x = 500x - 90,000
140x - 500x = -90,000
-360x = -90,000
x = (-90,000)/(-360)
x = 250
The speed of the plane is 250 mph
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Extra info:
The car's speed is x-180 = 250-180 = 70 mph
It takes the plane t = d/r = 500/250 = 2 hours and it takes the car t = d/r = 140/70 = 2 hours. Both vehicles travel for 2 hours, which helps to confirm the answer.
