Answer:
Billy Bob Joe now has 18 jelly beans left
Explanation:
Bob initially has 77 jelly beans, Sally initially has 12 jelly beans and Billy Bob Joe initially has 19 jelly beans.
If Bob gives 45 jelly beans to Sally, Bob now has 77 - 45 = 32 jelly beans and Sally now has 12 + 45 = 57 jelly beans.
Sally now gives 29 jelly beans to Billy Bob Joe. Sally now has 57 - 29 = 28 jelly beans and Billy Bob Joe now has 19 + 29 = 48 jelly beans.
If Billy Bob Joe now eats 30 jelly beans, he now has 48 - 30 = 18 jelly beans.
So, after eating 30 jelly beans, Billy Bob Joe now has 18 jelly beans left.