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.

[EX Q]: Question: Two pipes A and B can separately fill a cistern in 10 and 15 minutes respectively. A person opens both the pipes together when the cistern should have been was full he finds the waste pipe open. He then closes the waste pipe and in another 4 minutes the cistern was full. In what time can the waste pipe empty the cistern when fill?

Option A: 7

Option B: 9

Option C: 5

Option D: 4

Option E: 8
[EX A]: Option E

[EX Q]: Question: As a treat for her two children, a mother runs to the freezer in which she has three cherry ice pops, three orange ice pops, and four lemon ice pops. She chooses two at random to bring outside to the children, but realizes as she runs out the door that she cannot bring them different flavors without one being jealous of the other and getting even more upset. What is the probability that she has to return to the freezer to make sure that they each receive the same flavor?

Option A: 2/5

Option B: 3/7

Option C: 7/12

Option D: 11/15

Option E: 17/25
[EX A]: Option D

[EX Q]: Question: A carpenter makes 4 bunk beds every day. A military school needs to organize a place to sleep for 143 soldiers. If there are 5 carpenters working on the job, how many whole days in advance should they receive the order and start working in order to finish the right number of beds assuming that each bunk- bed is used by two soldiers?

Option A: 3.

Option B: 4.

Option C: 5.

Option D: 6.

Option E: 7.
[EX A]:
Option C