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: All of the citizens of a country have a six-character or seven-character national identification code that is created using the 26 letters of the alphabet and the 10 digits from 0 to 9. What is the maximum number of citizens who can be designated with these codes?

 Option A: 36^13

 Option B: 35(36^7

 Option C: 37(36^6

 Option D: 35(36^6

 Option E: 37(36^7

Answer: Option C


Question: 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.2.9

 Option B: Rs.2.1

 Option C: Rs.2.5

 Option D: Rs.2.2

 Option E: Rs.2.7

Answer: Option C


Question: Question: Working alone, machine X can manufacture 1,000 nails in 10 hours. Working together, machines X and Y can manufacture 1,000 nails in 5 hours. How many hours does it take machine Y to manufacture 1,000 nails working alone?

 Option A: 3 9/17

 Option B: 5 1/3

 Option C: 10

 Option D: 11 1/5

 Option E: 18 4/7

Answer:
Option C