Math 151 question

Question

A plane can fly 550 miles in the same time as it takes a car to go 150 miles. If the car travels 80 mph slower than the plane, find the speed of the plane.

Answer 1

distance = speed times time

d= st

t = d/s = 550/p = 150/(p-80)

cross multiply

550p - 44000 = 150p

400p = 44000

p = 110 mph = plane's speed

p-80 = 30 mph = car's speed

it takes the plane 5 hours to go 550 miles

and it takes the car 5 hours to go 150 miles

550/5 = 110 mph

150/5 = 30 mph = 110-80