You can
put this solution on YOUR website!The important consideration in this problem is that Grace has to be positive she has one
jellybean of each color. That means that she must be in a position that her last draw
must be the third color.
.
There is a possibility that Grace could draw 8 red jellybeans in a row and then could draw
4 blue ones in a row. Then since there are only green ones left her next draw would have to
give her the missing color. This is 13 jellybeans drawn.
.
She could also draw 8 red ones in a row followed by 4 green ones. But the next draw would
have to be blue. Again this is 13 jellybeans drawn.
.
If she were lucky, she could draw one jellybean of each color in 3 picks, but she could
not be sure that she would have one of each color. She also might do it in 4 picks, or
5, or 6, or 7, or 8, or 9, or 10, or 11, or 12. But to be absolutely sure she has one bean
of each color she must draw 13 times.
.
Hope this helps you to think your way through the problem.