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.

Q: Question: On an order of 5 dozen boxes of a consumer product, a retailer receives an extra dozen free. This is equivalent to allowing him a discount of:

 Option A: 15%

 Option B: 16 1/6%

 Option C: 16 2/3%

 Option D: 20%

 Option E: 30%

A: Option C
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Q: Question: The original price of a shirt was $20. It was decreased to $15 . What is the percent decrease of the price of this shirt.

 Option A: 25%

 Option B: 35%

 Option C: 45%

 Option D: 55%

 Option E: 65%

A: Option A
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Q: Question: The speed of a train is 72 kmph. What is the distance covered by it in 20 minutes?

 Option A: 20 kmph

 Option B: 28 kmph

 Option C: 25 kmph

 Option D: 22 kmph

 Option E: 24 kmph

A:
Option E
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