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: 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: A car traveled 75% of the way from Town A to Town B at an average speed of 75 mph. The car traveled at an average speed of v mph for the remaining part of the trip. The average speed for the entire trip was 50 mph. What is v in mph?

 Option A: 30

 Option B: 35

 Option C: 25

 Option D: 40

 Option E: 45

A: Option C
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Q: Question: Kim bought a total of $2.65 worth of postage stamps in four denominations. If she bought an equal number of 5-cent and 25-cent stamps and twice as many 10-cent stamps as 5-cent stamps, what is the least number of 2-cent stamps she could have bought ?

 Option A:  5

 Option B:  10

 Option C:  7.5

 Option D:  20

 Option E:  25

A:
Option C
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