Question

[2] (c) Another bag contains 15 red beads and 10 yellow beads. Ariana picks a bead at random, records its colour and replaces it in the bag. She then picks another bead at random. (1) Find the probability that she picks two red beads. [2] (ii) Find the probability that she does not pick two red beads. (0)​

Answer 1

(c)

Total number of beads:

• 15 + 10 = 25

(i)

Probability of 2 red:

• P(RR) = 15/25*15/25 = 9/25

(ii)

Probability of no 2 red:

• P(R'R') = 1 - 9/25 = 16/25