Problem

A multiple choice exam has 10 questions. Each question has 4 possible answers, of which only 1 is correct. If a student guesses on each question, what is the probability that the student will get exactly 6 questions correct?

Answer

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Answer

Step 6: Multiply all these values together to find the probability: P(X=6)=2100.0002441406250.31640625=0.01614

Steps

Step 1 :Step 1: Identify the values for the formula of binomial distribution. In this case, n (number of trials) is 10, k (number of successes) is 6, and p (probability of success on a single trial) is 0.25 (since there's 1 correct answer out of 4).

Step 2 :Step 2: Plug these values into the formula for the binomial probability: P(X=k)=C(n,k)pk(1p)nk

Step 3 :Step 3: Calculate the binomial coefficient C(n, k) which is C(10,6)=10!6!(106)!=210

Step 4 :Step 4: Calculate pk=(0.25)6=0.000244140625

Step 5 :Step 5: Calculate (1p)nk=(0.75)4=0.31640625

Step 6 :Step 6: Multiply all these values together to find the probability: P(X=6)=2100.0002441406250.31640625=0.01614

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