Respuesta :
Answer:
bus = 50mph and train = 70mph
Step-by-step explanation:
4b + 4t = 480
t = b + 20 [replace the "t" in the next step to solve]
4b + 4(b + 20) = 480
4b + 4b + 80 = 480
8b + 80 = 480 [subtract 80 from both sides of the equation]
8b = 400 [divide by 8 on both sides of the equation]
b = 50 and if the train is 20mph faster, t = 70
4(50) + 4(70) = 480