AMC 10B 2010 Problem 14

The average of the numbers 1,2,3, \ldots, 98,99, and x is 100 x. What is x ?

Answer Choices
A. \dfrac{49}{101}
B. \dfrac{50}{101}
C. \dfrac{1}{2}
D. \dfrac{51}{101}
E. \dfrac{50}{99}