Answer:
26.17%
Step-by-step explanation:
P(Grey) = 1/4
P(Grey at least 2 times in 4) = 1 - P(no Grey in 4) - P(1 Grey in 4)
P(no Grey in 4) = 4C0 * 3/4 * 3/4 * 3/4 * 3/4 = 81/256
P(1 Grey in 4) = 4C1 * 1/4 * 3/4 * 3/4 * 3/4 = 27/64
P(Grey at least 2 times in 4) = 1 - 81/256 - 27/64 = (256-81-108)/256=67/256=26.17%
