In a stack of cards, 11 cards are blue and the rest are red. If 2 cards are to be chosen at random from the stack without replacement, the probability that the cards chosen will both be blue is 5/6 . What is the number of cards in the stack?	Choices:
A) 10
B) 11
C) 12
D) 15
E) 18
This question can be solved by TESTing THE ANSWERS.   Answer C: 12 total cards   With 12 total cards, and 11 blue cards, the probability of pulling two blue cards is...   (11/12)(10/11) = 110/132 ~= 5/6   This is an exact MATCH for what we were told, so this MUST be the answer.   Final Answer:   12
<result>C</result>
In a stack of cards, 11 cards are blue and the rest are red. If 2 cards are to be chosen at random from the stack without replacement, the probability that the cards chosen will both be blue is 5/6 . What is the number of cards in the stack?