SOLUTION: A plane can fly 320 miles in the same time as it takes a car to go 120 miles. If the car travels 100 mph slower than the plane, find the speed of the plane.

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Question 702530: A plane can fly 320 miles in the same time as it takes a car to go 120 miles. If the car travels 100 mph slower than the plane, find the speed of the plane.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Which Vehicle----Speed-------------Time-------------Distance
Car:___________r-100___________t____________120
Plane:__________r_______________t____________320

Time is the same for both.
Car: t=120%2F%28r-100%29
Plane: t=320%2F%28r%29

120%2F%28r-100%29=320%2Fr
3%2F%28r-100%29=4%2Fr
3%2Ar=4%2A%28r-100%29
...
r=400 miles per hour