### SAT Prep Class: Determining the Mean

Bestselling Learn Guitar on Android! http://bit.ly/LearnGuitarAndroid SAT Prep Question #9 Question: What is the average (arithmetic mean) of -x, x, 2x, 3x, 7x? Most people are already familiar with the standard way of determining averages. This involves adding up all the data points in the set and dividing by the number of points.? This problem is no different from a regular averages problem. The only difference is that you don't know the exact data points. Instead, you know them in terms of "x." But don't let that confuse you. The problem is solved the same way as a standard averages problem. ? Solve the Problem 1. First add up all the data points in the set. Since your points include "x," you'll have to write the equation differently than usual:? -x+x+2x+3x+7x? ? ? ? ? ? ?5 2. Now you can simplify the equation to solve the problem. Add up all the "x" data points to get: 12x ?5 You can't simplify the problem any further until you find out the value of "x" so this is the final answer. Read more by visiting our page at: http://www.mahalo.com/courses/sat-math-prep/practice-questions/determining-the-mean/

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