instruction:
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:
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
answer:
Option B


question:
Question: If f(y)=y^2 and y is a positive integer, which of the following CANNOT be the value of f(f(y))?

 Option A: 1

 Option B: 144

 Option C: 81

 Option D: 16

 Option E: 256
answer:
Option B


question:
Question: The banker's discount on Rs.1800 at 16% per annum is equal to the true discount on Rs.1872 for the same time at the same rate. Find the time?

 Option A: 3 months

 Option B: 4 months

 Option C: 5 months

 Option D: 6 months

 Option E: 7 months
answer:

Option A