Question

A bus and a car leave from the same city traveling in opposite directions. The bus leaves 2 hours before the car does. The bus travels at a steady speed of 50 mph while the car travels at 70 mph. After how many hours will the bus and car be 800 miles apart?

If h represents the number of hours the bus travels, then which of the following expressions represents the number of miles the car travels?

Answer 1

h=number of hours the bus travels
(h-2)=number of hours the car travels

speed=distance/time  ⇒distance=speed x time

If h represent the number of hours the bus travels, the number of miles the car travels will be:
distance=speed x time

Data:
speed=70 mph
time=(h-2)

Distance : 70(h-2)

Answer ₂= the following expressions represents the number of miles the car travels:  70(h-2)            or      (70h-140)


We can suggest the following equation if we want to find out the number of hours spent, when the bus and car are 800 miles apart.
50h+70(h-2)=800

50h+70h-140=800
120h=800+140
120h=940
h= 940/120
h=7.833...≈7.83

Answer: 7.83 hours after the bus left the city, the car and the bus will be 800 miles apart.