MathDB
List of Integers

Source:

February 27, 2008
algebrasystem of equations

Problem Statement

When 15 15 is appended to a list of integers, the mean is increased by 2 2. When 1 1 is appended to the enlarged list, the mean of the enlarged list is decreased by 1 1. How many integers were in the original list? <spanclass=latexbold>(A)</span> 4<spanclass=latexbold>(B)</span> 5<spanclass=latexbold>(C)</span> 6<spanclass=latexbold>(D)</span> 7<spanclass=latexbold>(E)</span> 8 <span class='latex-bold'>(A)</span>\ 4 \qquad <span class='latex-bold'>(B)</span>\ 5 \qquad <span class='latex-bold'>(C)</span>\ 6 \qquad <span class='latex-bold'>(D)</span>\ 7 \qquad <span class='latex-bold'>(E)</span>\ 8