Question

Increasing the average speed of a car by 12mph results in a 189 mile trip taking an hour less than before. What was the original speed of the car?

Answer 1

To answer this item, we let the original speed of the car be x. The time it take to travel a certain distance is calculated by dividing the distance by the speed. Using the condition given above,
                                 189 / (x + 12) = 189/x - 1
The value of x from the equation is 42 mph. Thus, the original speed of the car is 42 mph.