Question

I drive to a house at 40 mph and drive back at 45 mph, the trip took 4 hours how long was my trip?

Answer 1

Distance=speed*time

Answer 2

wait what about the trip in one direction?

Answer 3

40x=45y
x+y=4
x = time taken to go the house
y = time taken to return

Answer 4

x=4-y
substitute this in 40x=45y