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: Working alone at its constant rate, machine K took 3 hours to produce 1/5 of the units produced last Friday. Then machine M started working and the two machines, working simultaneously at their respective constant rates, took 6 hours to produce the rest of the units produced last Friday. How many hours would it have taken machine M, working alone at its constant rate, to produce all of the units produced last Friday?

 Option A: 10

 Option B: 12

 Option C: 15

 Option D: 25

 Option E: 30

A: Option C
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Q: Question: The population of a certain town increases by 50 percent every 50 years. If the population in 1950 was 810, in what year was the population 160?

 Option A: 1650

 Option B: 1700

 Option C: 1750

 Option D: 1800

 Option E: 1850

A: Option C
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Q: Question: When processing flower-nectar into honey bees' extract, a considerable amount of water gets reduced. How much flower-nectar must be processed to yield 1kg of honey, if nectar contains 50% water, and the honey obtained from this nectar contains 35% water?

 Option A: 1.3 kg

 Option B: 1.5 kg

 Option C: 1.7 kg

 Option D: 1.9 kg

 Option E: None of these

A:
Option A
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