You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.
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Question: Question: The probability that a visitor at the mall buys a pack of candy is 30%. If three visitors come to the mall today, what is the probability that exactly two will buy a pack of candy?

 Option A: 343

 Option B: 147

 Option C: 189

 Option D: 063

 Option E: 027

Answer: Option C


Question: Question: (3x + 1) (2x - 5) = ax^2 + kx + n . What is the value of a - n + k ?

 Option A: 5

 Option B: 8

 Option C: 9

 Option D: 14

 Option E: 11

Answer: Option D


Question: Question: A and B complete a work in 6 days. A alone can do it in 10 days. If both together can do the work in how many days?

 Option A: 3.95 days

 Option B: 4.95 days

 Option C: 3.75 days

 Option D: 2.50 days

 Option E: 1.45 days

Answer:
Option C