This problem is from the quant questions on GregMAT. In the solution video, Greg backsolves by inputting the answer options to the combination formula to get the number of ways to guess two letters. He then says that there is only one correct letter (to win the lottery), so his final probability is 1/the result of the combination formula. I don’t understand how, from the question, we can know that there is only one letter that wins the lottery. I mean, the question says “must correctly guess TWO random, distinct letters.” So I had assumed it would be 2/# ways, not 1/# ways. I want to understand so I don’t repeat the same mistake again.
Since the winning guess consists of two specific letters, there is only one correct combination. The fact that the guess includes two letters doesn’t mean there are two winning outcomes, it’s still just one unique correct guess. So, the probability is 1 / (total ways to pick two letters)."
omg this makes so much sense thanks!
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