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 reduction of 20% in the price of salt enables a lady to obtain 10kgs more for Rs.100, find the original price per kg?

 Option A: Rs.3.2

 Option B: Rs.2.9

 Option C: Rs.2.5

 Option D: Rs.5.2

 Option E: Rs.2.1

A: Option C
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Q: Question: How much time does a train 150 metres long running at 90 km/hr take to pass a pole?

 Option A: 7.9s

 Option B: 6s

 Option C: 7.5s

 Option D: 7.6s

 Option E: 7.4s

A: Option B
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Q: Question: A tank has both an inlet pipe and an outlet pipe. Working alone, the inlet pipe can fill up the tank in 4 hours. Working alone, the outlet pipe can empty out the tank in 8 hours. If it is desired that the tank should be filled, from empty, exactly 6 hours after the inlet pipe is turned on at 9:30am, then at what time should the outlet pipe be opened ?

 Option A: 11:00am

 Option B: 10:30am

 Option C: 9:30am

 Option D: 10:00am

 Option E: 11:30am

A:
Option E
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