Question

A drawer contains 5 red socks, 9 white socks, and 6 blue socks. Without looking, you draw out a sock and then draw out a second sock without returning the first sock.
Find P(blue, then blue).
Your answer:

Answer 1

P = Number of favourable outcomes ÷ Sum of total outcomes

So, Probability of drawing a blue sock is

Number of blue socks ÷ Number of total socks

= 6 ÷ 20

= 3 ÷ 10

= 0.3

Now as we have drawn a sock already the total number of socks in the drawer are 19

So, the probability of drawing a blue sock now will be :

= 6 ÷ 19

= 0.31