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.
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Question: Question: A table is bought for Rs.400/- and sold at Rs.600/- find gain or loss percentage

 Option A: 15%loss

 Option B: 10%gain

 Option C: 30%gain

 Option D: 20%loss

 Option E: 50% gain

Answer: Option E


Question: Question: Two trains are moving at 60 kmph and 70 kmph in opposite directions. Their lengths are 150 m and 100 m respectively. The time they will take to pass each other completely is?

 Option A: 5 sec

 Option B: 6 sec

 Option C: 7 sec

 Option D: 8 sec

 Option E: 9 sec

Answer: Option C


Question: Question: What number should be added to each of the numbers 8, 21, 13 and 31 so that the resulting numbers, in this order form a proportion?

 Option A: 2

 Option B: 3

 Option C: 5

 Option D: 7

 Option E: 9

Answer:
Option C