Answer: 0.9819
Explanation:
Binomial probability formula :-
, where P(x) is the probability of getting success in x trials, n is total number of trials and p is the probability of getting succes in each trial.
Given : The probability of success :

The total question answered : n= 15
Now, the probability that the number of correct answers is at most 6 is given by :-

Hence, the probability that the number of correct answers is at most 6 = 0.9819