Permutation and combination

Question

There are 5 doors to a room. Two are red and the others are green. In how many ways can a person enter the room and leave the room from different coloured doors? 

Answer 1

If you enter through a red and exit through green, you have 2*3 or 6 ways to do it. If you enter through green and exit through red, you still have 6 ways (3*2). So you have 12 possible wa altogether