I drive at an average speed of 30 miles per hour to the railroad station each morning and just manage to catch my train on time.
On a particular morning there was a lot of traffic and at the halfway point I found I had averaged only 15 miles per hour.
How fast must I drive for the rest of the way to catch my train?
The train is about to leave and you will not be able to catch the train.
The amount of time taken to travel to the halfway point at 15 miles an hour is the same amount of time taken to reach the train station when travelling to the railroad station at 30 miles an hour.
For example, let’s assume that the distance to travel is 30 miles.
When travelling at 30 miles an hour, it takes 1 hour.
When travelling at 15 miles an hour, it will already take 1 hour to reach the halfway point.