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
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Q: Question: If p and q are positive integers each greater than 1, and 17(p+1)=20(q+1), what is the least possible value of p+q?

 Option A: 35

 Option B: 42

 Option C: 44

 Option D: 46

 Option E: none

A: Option A
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Q: Question: The average weight of 16 children in a class is 50.25 kg and that of the remaining 8 children is 45.15 kg. Find the average weights of all the children in the class.

 Option A: A

 Option B: B

 Option C: C

 Option D: D

 Option E: E

A:
Option A
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