Math Problem Statement

Points X, Y, and Z lie on a number line at -2, 0, and x3, respectively. Point X weighs twice as much as point Y, and point Z weighs three times as much as point Y. The weighted average is located at 4/3. Explain how to find the location of point Z.

Solution

We are given that points XX, YY, and ZZ lie on a number line at positions 2-2, 00, and x3x_3, respectively. The weights of these points are as follows:

  • Point XX has twice the weight of point YY.
  • Point ZZ has three times the weight of point YY.
  • The weighted average of the three points is located at 43\frac{4}{3}.

To find the location of point ZZ, we use the formula for a weighted average:

Weighted average=wXxX+wYxY+wZxZwX+wY+wZ\text{Weighted average} = \frac{w_X x_X + w_Y x_Y + w_Z x_Z}{w_X + w_Y + w_Z}

Where:

  • wXw_X, wYw_Y, and wZw_Z are the weights of points XX, YY, and ZZ, respectively.
  • xXx_X, xYx_Y, and xZx_Z are the positions of points XX, YY, and ZZ.

Step-by-Step Solution:

  1. Assign weights:

    • Let the weight of point YY be wY=1w_Y = 1.
    • The weight of point XX is wX=2w_X = 2, since it weighs twice as much as YY.
    • The weight of point ZZ is wZ=3w_Z = 3, since it weighs three times as much as YY.
  2. Substitute positions and weights:

    • The position of XX is xX=2x_X = -2.
    • The position of YY is xY=0x_Y = 0.
    • The position of ZZ is xZx_Z (which we need to find).
    • The weighted average is given as 43\frac{4}{3}.

Now, substitute all these into the weighted average formula:

43=2(2)+1(0)+3(xZ)2+1+3\frac{4}{3} = \frac{2(-2) + 1(0) + 3(x_Z)}{2 + 1 + 3}

  1. Simplify the equation: 43=4+0+3xZ6\frac{4}{3} = \frac{-4 + 0 + 3x_Z}{6} 43=4+3xZ6\frac{4}{3} = \frac{-4 + 3x_Z}{6}

  2. Multiply both sides by 6 to eliminate the denominator: 8=4+3xZ8 = -4 + 3x_Z

  3. Solve for xZx_Z: 8+4=3xZ8 + 4 = 3x_Z 12=3xZ12 = 3x_Z xZ=4x_Z = 4

Final Answer:

The location of point ZZ is xZ=4x_Z = 4.


Do you want any further clarification on this solution?

Here are 5 related questions to expand your understanding:

  1. What is the general formula for a weighted average in higher dimensions?
  2. How would the solution change if point ZZ had a different weight, say twice the weight of point YY?
  3. How does the concept of center of mass relate to weighted averages in mathematics?
  4. If the points were on a 2D plane, how would the weighted average be calculated?
  5. How can we apply weighted averages in probability and statistics?

Tip: Always check the sum of weights when dealing with weighted averages to ensure accuracy in calculations.

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Math Problem Analysis

Mathematical Concepts

Weighted Average
Algebra
Number Line

Formulas

Weighted average formula: (w_X * x_X + w_Y * x_Y + w_Z * x_Z) / (w_X + w_Y + w_Z)

Theorems

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Suitable Grade Level

Grades 9-11