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1. The probability that a student will get exactly 13 questions right is 0.003.

   Let E be an event that student gives 13 right answers.

   According to the given question.

   An exam contain total number of questions is 15.

   Now,

   The probability that a student gives a right answer, p = 1/2 = 0.5

   And, the probability that a student gives a wrong answer, q = 1 – 1/2 = 1/2 = 0.5

   Therefore,

   The probability that a student will get exactly 13 questions right is given by

   ⇒ P(E) = C(15, 13) p^(13)q^(15 – 13)

   ⇒ P(E) = (15!/13!2!)(0.5)^13(0.5)^2

   ⇒ P(E) = (15(14)/2 ) ×  ( 0.00012) × 0.25

   ⇒ P(E) = 105 × 0.00012 × 0.25

   ⇒ P(E) = 0.00315

   Hence, the probability that a student will get exactly 13 questions right is 0.003.

   Find out more information about probability here:

   https://brainly.com/question/2147705

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