Question

There are 9 yellow and 4 purple balls in a bag. If you randomly choose balls one at a time, with replacement, what is the probability of choosing 1 yellow ball and then 2 purple balls?

165/5210

24/1329

144/2197

28/1335

Answer 1

9+4 = 13 total balls

1st pick would be 9/13 probability of picking yellow

2nd pick would be 4/13 probability

3rd pick would be 4/13 probability

 total probability : 9/13 * 4/13 * 4/13 = 144/2197