Identify if it is a binomial experiment or not

Question

A multiple choice test has 4 questions and each question has 3 choices (A,B, and C) of which only one is the correct answer.A student passes the test if she/he gets 3 or more answers correct.

Answer 1

It is binomial...

p=1/3 , q = 1-p = 1 - 1/3 = 2/3

Probability of passing the test is 3 or 4 successes in 4 trials...

(4 choose 3) * (1/3)^3 * (2/3) + (4 choose 4) * (1/3)^4 * (2/3)^0 =

4 * (1/81) * 2/3 + 1/81 =

(8/3)(1/81) + (1/81) = (11/3)(1/81) = 11/243 = 4.52...%