math
posted by A on .
Yosuf has three grey socks and four blue socks in his sock drawer. He pulls out a pair of socks in the dark.
(a) What is the total number of possible outcomes?
(b) What is the probability that the pair of socks selected is grey?
(c) What is the probability that the pair of socks selected is blue?
(d) What is the probability that the pair of socks selected is neither grey nor blue?

a) 3 outcomes:
GG , GB, BB
b) 3 G, and 4B
prob (GG) = (3/7)(2/6) = 1/7
c) prob (BB) = ((4/7)(3/6) = 2/7
d) prob(not both blue or grey)
= prob (BG) + prob(GB)
= (4/7)(3/6) + (3/7)(4/6)
= 2/7 + 2/7 = 4/7
or we could have taken
1  (1/7+2/7) = 4/7