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: A man can row a boat at 20 kmph in still water. If the speed of the stream is 6 kmph, what is the time taken to row a distance of 66 km downstream?

 Option A: 30/83 hours

 Option B: 33/13 hours

 Option C: 31/13 hours

 Option D: 30/13 hours

 Option E: 30/14 hours
answer:
Option B


question:
Question: If the wheel is 21 cm then the number of revolutions to cover a distance of 1056 cm is?

 Option A: 8

 Option B: 27

 Option C: 10

 Option D: 7

 Option E: 19
answer:

Option A