To return home from school I always use the bicycle. There are two possible paths to get to my house: the first one is completely flat and the second one goes up halfway and the other half down. When I go on the way up the circle, it is twice as slow as when I go on the flat, but on the way down I go twice as fast, so it will take me the same to arrive regardless of the path I take.

**Is this true? What is the fastest way?**

#### Solution

The boy is wrong because if it is twice as slow on the rise as it is in the flat, it will take twice as much to do the ascent part that is half the flat road or what is the same, it will take the same to do the whole flat path that the whole part of the climb that is half the full path, so it will take longer if you take the road that is not flat.