When rolling two six-sided dice, what is the probability of rolling a total combination of five, given that one die rolls a one?

I believe this is conditional probability, P(E1|E2). My professor suggested this answer:

P(rolling a combination of 5 and player rolls a one) / P(player rolls a one) = (2/36) / (11/36) = 2/11

I don't understand why the denominator P(player rolls a one) would equal 11/36 and not 1/6.

What is the best way to solve this problem?