There are four routes, A, B, C, and D, between a person’s home and the place where he works, but route B is one-way, so he cannot take it on the way to work, and route C is one-way, so he cannot take it on the way home.
(a) Draw a tree diagram showing the various ways the person can go to and from work.
(b) Draw a tree diagram showing the various ways he can go to and from work without taking the same route both ways.