The key to solving application problems is to find out the meaning of the problem and list the equations, but the equivalence relation is not so obvious in this problem, so students should carefully understand the meaning of the problem and find out the equivalence relation. The equivalent relationship in this problem is: the distance that this person walks in 6 minutes is equal to the distance that the tram catches up with it in 6 minutes; Every 2 minutes, a tram runs from the opposite side to the back;

(2) According to the meaning of the question, a tram runs from behind him to the front every 6 minutes, that is, the distance that this person travels in 6 minutes is equal to the distance that the tram catches up with it in 6 minutes, thus listing Equation 6 (v1-v2) = v1t;

(3) According to the fact that a tram runs from the opposite side to the back every 2 minutes, we can list the equations of 2(v 1+v2)=v 1t and find out the time of t..

Solution: According to the meaning of the question: 6 (v1-v2) = v1t 2 (v1+v2) = v1t?

The solution is v 1=2v2∴t=3 (minutes).

A: The tram runs every three minutes.