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 a partly cloudy day, Derek decides to walk back from work. When it is sunny, he walks at a speed of s miles/hr (s is an integer) and when it gets cloudy, he increases his speed to (s + 1) miles/hr. If his average speed for the entire distance is 2.8 miles/hr, what fraction Q of the total distance did he cover while the sun was shining on him?

 Option A: 1/4

 Option B: 4/5

 Option C: 1/5

 Option D: 1/6

 Option E: 1/7

A: Option E
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Q: Question: What percent of 60 is 70?

 Option A: 133 1⁄3

 Option B: 75

 Option C: 60

 Option D: 33 1⁄3

 Option E: 116.66

A: Option E
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Q: Question: John bought 15 apples for Rs.10 and sold them at the rate of 12 apples for Rs.12. What is the percentage of profit made by him?

 Option A: 50 %

 Option B: 60 %

 Option C: 65 %

 Option D: 100 %

 Option E: None

A:
Option A
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