Question

Using drt what is the Answer to this question a car in a bus set out at 2 PM find the same point headed in the same direction. The average speed of the car is 30 mph slower than twice the speed of the bus. In two hours the car is 20 miles ahead of the bus. Find the rate of the car

Answer 1

Answer: the rate of the car is 50mph

Step-by-step explanation:

Let x represent the average speed of the bus.

Let y represent the distance travelled by the bus.

The average speed of the car is 30 mph slower than twice the speed of the bus. This means that the average speed of the car would be

2x - 30

Distance = speed × time

Time = distance/speed

Therefore, In 2 hours time,

2 = y/x

2x = y

In two hours the car is 20 miles ahead of the bus. Therefore

2 = (y + 20)/(2x - 30)

2(2x - 30) = y + 20

4x - 60 = y + 20 - - - - - - - - -1

Substituting y = 2x into equation 1, it becomes

4x - 60 = 2x + 20

4x - 2x = 20 + 60

2x = 80

x = 80/2 = 40

The speed of the car would be

2x - 30 = 2 × 40 - 30

= 80 - 30 = 50 mph