A student averages 70% on mult choice tests. What is the probability that he misses the first 3 questions until he gets a question correct?

Question

I think I know the answer I just want to go over it just to make sure that I am doing things correctly. I thought the answer is 30 percent but I am not sure how I am getting this answer.

Answer 1

The probability of getting any one question right is p = 0.7 and of getting it wrong is 1-p = 0.3.

One wrong to start = (0.03)

Two wrong to start = (0.3)(0.3) = 0.09

Three wrong to start = (0.3)(0.3)(0.3) = (0.3)^3 = 0.027.