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: One-tenth of the students at a nursery school are 4 years old or older. If 20 students have not yet reached their third birthday, and a total of 50 students are not between 3 years old and 4 years old, how many children are in the nursery school?

 Option A: 150

 Option B: 300

 Option C: 450

 Option D: 490

 Option E: 620
[A]: Option B


[Q]: Question: Three candidates contested in an election and received 6136, 7636, 11628 votes respectively. What is the percentage of the total votes did the winning candidate get?

 Option A: 46%

 Option B: 49%

 Option C: 57%

 Option D: 51%

 Option E: 62%
[A]: Option A


[Q]: Question: Pipe A can fill a tank in 5 hours, pipe B in 10 hours and pipe C in 30 hours. If all the pipes are open, in how many hours will the tank be filled?

 Option A: 2

 Option B: 3

 Option C: 3.5

 Option D: 4

 Option E: 4.5
[A]:
Option B