Devon travels 40 km to Edmonton by car, and then returns by bus. The average speed of the car is 20 km/h greater than the average speed of the bus. If Devon's total travel time is 54 min, what is the average speed of the bus?

2 answers

Help needed urgently. Please Help.
since time = distance/speed, if the bus's speed is x, then

40/x + 40/(x+20) = 9/10

Now just find x, and x+20