- $\frac{2}{7}$
- $\frac{2}{5}$
- $\frac{3}{7}$
- $\frac{1}{2}$
- $\frac{3}{5}$

The probability of getting 2 yellow in a row is: $\frac{2}{8}\frac{1}{7}=\frac{1}{28}$.

The probability of getting 2 red in a row is: $\frac{4}{8}\frac{3}{7}=\frac{6}{28}$.

So the total probability is: \[\frac{1}{28}+\frac{1}{28}+\frac{6}{28}=\frac{2}{7}.\]

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Yup, starting tomorrow, I'll hide the answers behind spoiler tabs.

Using (n k) to stand for the binomial coefficient.

The answer is

(2 2) + (2 2) + (4 2)

---------------------

(28 2)

=

(# yellow pairs) + (# blue pairs) + (# red pairs)

-------------------------------------------------

(# total pairs)

We are choosing two socks each time, so we need to multiply the probability of choosing the first sock (something out of 8 with the prob. of choosing the second sock (something out of 7).

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