The average (arithmetic mean) of the integers from 200 to 400, inclusive, is how much greater than the average of the integers from 100 to 200, inclusive? Choose the correct choice from the following:
A) 150	B) 175	C) 200	D) 225	E) 300

Rationale: "for an ap the mean or average of series is average of first and last term . so , average of numbers between 200 to 400 , inclusive = ( 200 + 400 ) / 2 = 300 average of numbers between 100 to 200 , inclusive = ( 100 + 200 ) / 2 = 150 difference = 300 - 150 = 150 answer is a"
Answer: A