Problem #PRU-60335

Problem

a) In Wonderland, there are three cities $A$, $B$ and $C$. 6 roads lead from city $A$ to city $B$, and 4 roads lead from city $B$ to city $C$. How many ways can you travel from $A$ to $C$?

b) In Wonderland, another city $D$ was built as well as several new roads – two from $A$ to $D$ and two from $D$ to $C$. In how many ways can you now get from city $A$ to city $C$?