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: The length of a room is 7 m and width is 4.75 m. What is the cost of paying the floor by slabs at the rate of Rs. 900 per sq. metre.

 Option A: 25650

 Option B: 25750

 Option C: 26550

 Option D: 26750

 Option E: 29925

A: Option E
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Q: Question: The average salary per head of the entire staff of an office including the officers and clerks is Rs.90. The average salary of officers is Rs.500 and that of the clerks is Rs.84. If the number of officers is 2, find the number of officers in the office?

 Option A: 620

 Option B: 720

 Option C: 820

 Option D: 920

 Option E: 1020

A: Option C
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Q: Question: A part of certain sum of money is invested at 9% per annum and the rest at 21% per annum, if the interest earned in each case for the same period is equal, then ratio of the sums invested is?

 Option A: 4:2

 Option B: 4:8

 Option C: 7:3

 Option D: 4:0

 Option E: 4:9

A:
Option C
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