For 8.14, as a hint, since there are $1+2+3=6$ balls, in total there are $6\times 5 = 30$ ways for Alice and Bob to each pick a ball. ($6$ choices for Alice, $5$ choices for Bob).

For 8.28, remember $A^c$ is everything outside of $A$, so when we have $A\cup B^c$ we want everything inside $A$ OR outside $B$. This is almost everything in the sample space, what is missing? This hopefully can help start making progress. Drawing pictures can help visualize all the regions.

For 8.29, we'll take a look at the book, thanks for letting us know. The problem is meant to be an extension of 8.9, so now all three friends are trying to meet for dinner. For two friends we needed a $2$-dimensional interpretation (using areas). What might we want to use for three friends?

For 8.30, we know the triangle inequality helps us determine whether we can make a triangle out of three lengths. One of the sticks will have a length of $1$. We split the stick of length $2$ into two pieces. For example, if one piece has length $0.7$ the other has length $1.3$. How short can the shorter stick be to still make a triangle?

Hope these hints help, and let us know if you have more questions!