MathDB
Arithmetic Mean

Source:

January 21, 2006
modular arithmetic

Problem Statement

A set of consecutive positive integers beginning with 11 is written on a blackboard. One number is erased. The average (arithmetic mean) of the remaining numbers is 3571735\frac{7}{17}. What number was erased?
<spanclass=′latex−bold′>(A)</span>6<spanclass=′latex−bold′>(B)</span>7<spanclass=′latex−bold′>(C)</span>8<spanclass=′latex−bold′>(D)</span>9<spanclass=′latex−bold′>(E)</span>cannot be determined<span class='latex-bold'>(A) </span> 6\qquad <span class='latex-bold'>(B) </span>7 \qquad <span class='latex-bold'>(C) </span>8 \qquad <span class='latex-bold'>(D) </span> 9\qquad <span class='latex-bold'>(E) </span>\text{cannot be determined}
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