Question

Sock hop (ExH). You have 10 pairs of socks, fi ve black and fi ve blue, but they are not paired up. Instead, they are all mixed up in a drawer. It ’ s early in the morning, and you don ’ t want to turn on the lights in your dark room. How many socks must you pull out to guarantee that you have a pair of one color? How many must you pull out to have two good pairs (each pair is the same color)? How many must you pull out to be certain you have a pair of black socks?

Answer 1

Answer:

Step-by-step explanation:

Total number of pairs of socks in a drawer = 10

Number of black pairs of socks = 5

Number of blue pairs of socks  = 5

A. If you picked 2 socks [black] and [blue] 3rd pick guarantees you will have one pair of either blue or black

Number of socks you pull out to guarantee that you have a pair of one color = 3 socks

B. If you want to pick 2 good pairs and your 6 picks are worst case, so 7th pick of the socks will give you good pair of two colors.

Number of socks you pull out to have two good pairs = 7 socks

C. If you want to have a pair of black socks your worst case will be you pick all 10 blue socks so another 2 socks must be black.

Number of socks you pull out to have two black socks = 12 socks