Question

We are driving along a highway at a constant speed of 55 miles per hour (mph). You observe a car one half mile behind you. The car is moving fast and zooms past you exactly one minute later. How fast is this car traveling (mph) if its speed is constant?

Answer 1

Answer:

As given in the question the car is half mile behind.

So, the speed of the car will be 1/2 mile for 1 min.

Hence, accordingly 30 miles for 60 min(1 hr).

So, we can say that the speed of car was 30 mph.

While, from the question we know that speed of the car in which the observer is travelling with 55 mph.

Since, both the cars are moving in same direction the to find relative velocity we must add the speeds of the two cars.

Therefore, speed of the car = (55 + 30) mph

                                               =85mph.