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.

[Q]: Question: The cost of Type 1 material is Rs. 15 per kg and Type 2 material is Rs.20 per kg. If both Type 1 and Type 2 are mixed in the ratio of 2 : 3, then what is the price per kg of the mixed variety of material?

 Option A: Rs. 19

 Option B: Rs. 16

 Option C: Rs. 18

 Option D: Rs. 17

 Option E: Rs. 21
[A]: Option C


[Q]: Question: The number of diagonals of a polygon of n sides is given by the formula z=n(n-3)/2. If a polygon has twice as many diagonals as sides, how many sides does it have?

 Option A:  3

 Option B:  5

 Option C:  6

 Option D:  7

 Option E:  8
[A]: Option B


[Q]: Question: All of the stocks on the over-the-counter market are designated by either a 5-letter or a 5-letter code that is created by using the 26 letters of the alphabet. Which of the following gives the maximum number of different stocks that can be designated with these codes?

 Option A: 2(26^5

 Option B: 26(26^4

 Option C: 27(26^4

 Option D: 26(26^5

 Option E: 27(26^5
[A]:
Option A