Each question has only 2 choices: true or false. And therefore, for each question you have a 50% chance of getting it correct.
So the probability of getting them all correct is:
1/2*1/2*1/2*1/2*..... you'll do this n times for n questions. Therefore, the probability of getting them all correct is (1/2)^n
From the question, we can set the following inequality:
(1/2)^n<(1/1,000) (question asks for the probability to be less than 1/1,000)
=> 2^n>1,000
When n=10, 2^10=1,024. Therefore 10 is the least value for n to win by guessing randomly. I'm assuming n has to be an integer here because you cannot have fractional questions! So B.
