Alberto and Benito are two brothers who go to school every day by bus as they travel ten times faster than they walk. In the street where they live there are two stops on the same bus line and although they live together, Alberto always goes to the stop on the right that is closer and Benito always goes to the stop on the left, in the same sense in which the bus circulates. Curiously they always arrive at the school on the same bus. If Alberto takes nine minutes to get to his stop,

**How long does it take Benito to get his?**

#### Solution

**It will take 11 minutes**.

According to the statement, they always arrive on the same bus which means that either they catch it or they both lose it and must wait for the next one. This means that the time it takes for Benito to reach his stop is equal to the sum of the time it takes Alberto to get his stop plus the time it takes for the bus to go from one to another. One of them would take 9 + 11 = 20 minutes to walk from one stop to the other. The bus, which is 10 times faster, would take 2 minutes and therefore it is true that 2 = 11 - 9 which is the advantage of time Alberto had over Benito.