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 area of a parallelogram is 72sq m and its altitude is twice the corresponding base. Then the length of the base is?

 Option A: 6

 Option B: 9

 Option C: 7

 Option D: 62

 Option E: 2
Option A

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
Option E

Question: Find the arithmetic mean A of all roots of the following equation- see an attachment.

 Option A: 2

 Option B: 1

 Option C: 0.5

 Option D: -1/3

 Option E: 0.3

Option C