Question

The student answers 3 additional questions when passing the exam. The probability of

answering each question correctly is 0.21. Assuming that all the answers are independent events,

find the probability that at least two correct answers will be given

Answer 1

The probability that at least two correct answers will be given is:

$P(2,3) = C(2,3)×0.79×0.21^2 + 0.21^3 = 3×0.79×0.21^2 + 0.21^3 = 0.1138$ or 11.38%.