Question

A bag contains 9 red chips and 12 blue chips. Two chips are selected randomly without replacement from the bag. What is the probability that the two chips are the same color?

That would be the probability of two reds PLUS the probability of two blues.
The probability of two reds is (9/21)*(8/20) = 72/420 The probability of two blues is (12/21)*(11/20) = 132/420. The sum is 204/420 = 51/105 = 45.87% A magician asks you to pick a card, any card from a standard deck of 52 cards. What is the probability of picking an ace?
A magician asks you to pick a card, any card from a standard deck of 52 cards. What is the probability of picking an ace?
lucy fills a pot with a mixture of 1200 black beans and 300 white beans, all the same size. When she grabs a handful of 15 beans, she finds that 10 are black. What is the probability of choosing a white bean?

Answer 1

Since you already answered the first question, I'll answer the other two

1. There are four aces and 52 cards. Just divide 4 by 52 to get 1/13, or about 7.69%.

2. If you mean the probability of choosing white from the handful, that's (15-10)/15, or 1/3 (33.33%). However, in the mixture itself (combined with the handful), that's 300/1500, or 20%.