The A. P. Statistics exam consists of a multiple-choice section where each question has five choices. Sara estimates that she has a 75% chance of knowing each question. If she does not know the answer, she will randomly guess.

a) What is the probability of Sara getting a question correct?

b) The A. P. exam has 40 questions, how many might Sara expect to get correct?

Question

Mathematics

Diego Meadows

11 October, 18:59

The A. P. Statistics exam consists of a multiple-choice section where each question has five choices. Sara estimates that she has a 75% chance of knowing each question. If she does not know the answer, she will randomly guess.

a) What is the probability of Sara getting a question correct?

b) The A. P. exam has 40 questions, how many might Sara expect to get correct?

+2

Answers (1)

Know the Answer?

Koen Hampton · Answer 1

It's more than 75% because if she knows it that's 75% already, then you add 20% of the 25% she didn't know.

That's. 20 •.25 = 0.05 or 5%.

She actually has an 80% chance.

Then 0.80 • 40