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: A and B complete a work in 6 days. A alone can do it in 10 days. If both together can do the work in how many days?

 Option A: 3.75

 Option B: 3.76

 Option C: 3.79

 Option D: 3.74

 Option E: 3.71

Answer: Option A


Question: Question: The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is:

 Option A: 70 km/hr

 Option B: 75 km/hr

 Option C: 84 km/hr

 Option D: 87.5 km/hr

 Option E: 88.5 km/hr

Answer: Option D


Question: Question: Two hoses are pouring water into an empty pool. Hose 1 alone would fill up the pool in 6 hours. Hose 2 alone would fill up the pool in 5 hours. How long would it take for both hoses to fill up two-thirds of the pool?

 Option A: 5/12 hours

 Option B: 5/8 hours

 Option C: 20/11 hours

 Option D: 12/7 hours

 Option E: 12/5 hours

Answer:
Option C