Question asking the speed of and object compared to another

Question

A Plane can fly 480 miles in the same time it takes a car to go 180 miles. If the car travels 100 miles per hour slower than the plane find the speed of the plane?

Answer 1

d = r · t

 

480 = rt, 480 / r = t

180 = (r - 100)t, 180 / (r - 100) = t

 

480 / r = 180 / (r - 100)

 

Can you solve for r and answer?

 

Answer 2

Let P = plane speed and C = car speed.  Remember distance = rate * time i.e. time = distance/rate

 

C = P - 100

 

480/P = 180/C = 180/(P-100)

 

480P - 480*100 = 180P

 

300P = 480*100

 

P = 160 and C = 60