The sum of the even numbers between 1 and n is 89*90, where n is an odd number, then n=? Choose the correct choice from the following answers:
A) 167  B) 173  C) 179  D) 185  E) 193
Let n-1 = 2a.   2+4+...+2a = 2*(1+2+...+a) = 2*(a)(a+1)/2 = (a)(a+1) = 89*90   Then a = 89 and n = 179.   The answer is 179.
<result>C</result>
The sum of the even numbers between 1 and n is 89*90, where n is an odd number, then n=?