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.

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
Option C

Question: A car dealership has 40 cars on the lot, 30% of which are silver. If the dealership receives a new shipment of 80 cars, 40% of which are not silver, what percentage of total number of cars are silver?

 Option A: 35%

 Option B: 37.5%

 Option C: 45%

 Option D: 47.5%

 Option E: 50%
Option E

Question: A water tank is one-fifth full.Pipe A can fill a tank in 10 minutes and pipe B can empty it in 6 minutes.If both the pipes are open,how long will it take to empty or fill the tank completely?

 Option A: 6 min.to empty

 Option B: 9 min.to empty

 Option C: 5 min.to empty

 Option D: 4 min.to empty

 Option E: 3 min.to empty

Option E