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: A sum of $500 amounts to 600 in 2 years at simple interest. If the interest rate is increased by 10% it would amount to how much ?

 Option A: $500

 Option B: $700

 Option C: $800

 Option D: $600

 Option E: $300

A: Option B
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Q: Question: In a test, sixty percent students passed in Maths and 65% in History, 40% passed in both of these subjects. If 90 students failed in maths and history both, then what is the total number of students?

 Option A: 600

 Option B: 650

 Option C: 700

 Option D: 750

 Option E: None of these

A: Option A
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Q: Question: A sum of money place at compound interest doubles itself in 4 years. In how many years will it amount to eight times itself?

 Option A: 15 years

 Option B: 11 years

 Option C: 12 years

 Option D: 18 years

 Option E: 19 years

A:
Option C
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