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: Find compound interest on Rs. 5000 at 12% per annum for 1 year, compounded half-yearly.

 Option A: Rs. 600

 Option B: Rs. 618

 Option C: Rs. 525

 Option D: Rs. 620

 Option E: None

A: Option B
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Q: Question: The average marks of a class of 35 students is 45 and that of another class of 55 students is 65. Find the average marks of all the students?

 Option A: 52.6

 Option B: 52.4

 Option C: 52.1

 Option D: 57

 Option E: 52.9

A: Option D
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Q: Question: Excluding stoppages, the average speed of a bus is 60 km/hr and including stoppages, the average speed of the bus is 45 km/hr. For how many minutes does the bus stop per hour?

 Option A: 15

 Option B: 88

 Option C: 77

 Option D: 20

 Option E: 99

A:
Option A
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