On a particular mathematics exam, the student has 5 answers to choose from. If the student guesses at the answers, the probability of the student getting a correct answer on each question is 1/5. What is the least number of times that the student should guess in order to take the probability of getting a correct answer at least once to more than 50%. Answers
A) 4	B) 1	C) 2	D) 5	E) 6
Rule of Subtraction: P(A) = 1 - P(A')   Rule of Multiplication: P(A ∩ B) = P(A) P(B)   The probability that the student gets a correct answer at least once in 2 guesses is 1- (4/5)^2 = 1 - 16/25 = 9/25 &lt; 50%.   The probability that the student gets a correct answer at least once in 3 guesses is 1- (4/5)^3 = 1 - 64/125 = 61/125 &lt; 50%.   The probability that the student gets a correct answer at least once in 4 guesses is 1- (4/5)^4 = 1 - 256/625 = 369/625 &gt; 50%.   4nswer: 4
<result>A</result>
On a particular mathematics exam, the student has 5 answers to choose from. If the student guesses at the answers, the probability of the student getting a correct answer on each question is 1/5. What is the least number of times that the student should guess in order to take the probability of getting a correct answer at least once to more than 50%.