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: For any positive integer Y, the sum of the first Y positive integers equals Y(Y+1)/2 . If X and Y are positive integers and X > Y, what is the sum of all the integers between X and Y, inclusive?

 Option A:  X(X+1

 Option B:  X(X+1

 Option C:  X(X+1

 Option D:  X(X+1

 Option E:  X(Y+1

Answer: Option B


Question: Question: A library has an average of 1000 visitors on Sundays and 700 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is :

 Option A: 740

 Option B: 750

 Option C: 760

 Option D: 770

 Option E: 775

Answer: Option B


Question: Question: If 5 men undertook a piece of construction work and finished half the job in 15 days. If two men drop out, then the job will be completed in

 Option A: 5 days

 Option B: 15days

 Option C: 10 days

 Option D: 25days

 Option E: 20days

Answer:
Option D