TASK DEFINITION: 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.
PROBLEM: 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

SOLUTION: Option E

PROBLEM: Question: If the average (arithmetic mean) of five consecutive negative integers is 8k – 1, what is the difference between the greatest and least of the five integers?

 Option A: 4K

 Option B: 4k^2 -4k

 Option C: 4-4k

 Option D: 4

 Option E: 4k+4

SOLUTION: Option D

PROBLEM: Question: If 10,000 microns = 1 decimeter, and 10,000,000angstroms = 1 decimeter, how many angstroms equal 1 micron?

 Option A: 1.0e-08

 Option B: 1.0e-05

 Option C: 100,000

 Option D: 10,000

 Option E: 1,000

SOLUTION:
Option E