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: The total of the ages of Amar, Akbar and Anthony is 30 years. What was the total of their ages three years ago ?

 Option A: 20 years

 Option B: 28 years

 Option C: 71 years

 Option D: 21 years

 Option E: 31 years

Answer: Option D


Question: Question: In a poll of 44,000 dentists, only 30 percent responded; of these, 20 percent claimed to prefer Toothpaste A. How many of the dentists who responded did not claim a preference for Toothpaste A?

 Option A: 2,200

 Option B: 2,640

 Option C: 6,160

 Option D: 8,800

 Option E: 10,560

Answer: Option E


Question: Question: Krishan and Nandan jointly started a business. Krishan invested three times as Nandan did and invested his money for double time as compared to Nandan. If the gain is proportional to the money invested and the time for which the money is invested and the total gain was Rs. 28000, find the earning of Nandan.

 Option A: Rs.7000

 Option B: Rs.5000

 Option C: Rs.6000

 Option D: Rs.Rs.4000

 Option E: Rs.6500

Answer:
Option D