There are 3 ways in which you can answer each of the question in a 3 multiple-choice question. All in all, there are 27 ways in which Ling can answer the questions. Of these combinations, only one of which will give her a 100%. Thus,
probability = (1/27) x 100%
= 3.70%
Therefore, the probability that Ling will get 100% on the quiz is very lean with a value of only 3.70%.