The sum of the even numbers between 1 and n is 105*106, where n is an odd number, then n=?
Pick one:
A) 187	B) 193	C) 199	D) 205	E) 211

Rationale: let n - 1 = 2 a . 2 + 4 + . . . + 2 a = 2 * ( 1 + 2 + . . . + a ) = 2 * ( a ) ( a + 1 ) / 2 = ( a ) ( a + 1 ) = 105 * 106 then a = 105 and n = 211 . the answer is e .
Answer: E