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: Rob traveled a distance of 30 km, covering the first 10 km in x minutes, the next 10 km in y minutes and the last 10 km in z minutes. If he totally took 3y minutes to cover the whole distance, then which of the following cannot be true? Assume x , y and z are different.

 Option A: z=3x

 Option B: x=3z

 Option C: y=2x

 Option D: x=2y

 Option E: y=3x
answer:
Option D


question:
Question: man buys an article for 10% less than its value and sells it for 10% more than its value. His gain or loss percent is?

 Option A: 12

 Option B: 76

 Option C: 26

 Option D: 20

 Option E: 12
answer:
Option D


question:
Question: There are 10person among whom 2are brother. The total no.of ways in which these persons can be seated around a round table so that exactly 1person sit between the brothers, is equal to?

 Option A: 4!*2!

 Option B: 7!*2!

 Option C: 6!*1!

 Option D: 2!*1!

 Option E: 5!*1!
answer:

Option B