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: 23, 18, 16, 11, 9, 4 ?

 Option A: 3

 Option B: 2

 Option C: 7

 Option D: 5

 Option E: 1
Option B

Question: Two pipes P and Q can fill a cistern in 12 and 14 minutes respectively. Both are opened together, but at the end of 3 minutes the first is turned off. How much longer will the cistern take to fill?

 Option A: 11 1/2 min

 Option B: 11 1/4 min

 Option C: 11 2/4 min

 Option D: 11 1/5 min

 Option E: 10 1/2 min
Option E

Question: In a party there are 5 couples. Out of them 5 people are chosen at random. Find the probability that there are at the least two couples?

 Option A: 5/21

 Option B: 5/29

 Option C: 5/23

 Option D: 5/24

 Option E: 5/26

Option A