Question

Traffic along a stretch of road moves at an average speed that varies inversely with the number of cars on it. When there are 1500 cars, the average speed is 45 mi/h. What is the average speed when there are 1800 cars?

Answer 1

37.5 miles per hour

Explanation:

The traffic along a stretch road moves at an average speed that carried inversely as the number of cars

Average speed= k/number of cars.

When there are 1,500 cars the average speed is 45

The first step is to calculate the constant k

45= k/1500

k = 1,500 × 45

k= 67,500

Therefore the average speed when there are 1,800 cars can be calculated as follows

Average speed= 67,500/1,800

= 37.5 miles per hour

Hence the average speed is 37.5 moles per hour