## 57. The Speed of a Car.

- I was walking down the road at a speed of $3 \frac{1}{2}$ km/h,- said Mr. Pipkins,- when suddenly a car sped past me, nearly knocking me off my feet ${ }^{2}$.
- How fast was it going? - asked his friend.
- I'll tell you. From the moment it sped past me until it disappeared around the bend, I took 27 steps and then, without stopping, I walked another 135 steps to reach the bend.[^4]- Then we can easily determine the speed of the car, assuming that our speeds were constant.
57. Since a person takes 27 steps in the time it takes a car to travel a distance of 162 steps, it is clear that the car is moving 6 times faster than the person. The person moves at a speed of \(3 \frac{1}{2}\) km \(/ h\); therefore, the speed of the car is 21 km \(/ h\).