Question

Points X=15 and Y=45 are on a number line. If X is weighted at 20% and Y at 80%, what is the weighted average?(1 point)

Answer 1

To calculate the weighted average of points X and Y, you use the formula:

\[
\text{Weighted Average} = (X \cdot w_X) + (Y \cdot w_Y)
\]

where \( w_X \) is the weight for X and \( w_Y \) is the weight for Y.

Given:
- \( X = 15 \)
- \( Y = 45 \)
- \( w_X = 0.20 \)
- \( w_Y = 0.80 \)

Now, substitute these values into the formula:

\[
\text{Weighted Average} = (15 \cdot 0.20) + (45 \cdot 0.80)
\]

Calculating each term:

\[
15 \cdot 0.20 = 3
\]
\[
45 \cdot 0.80 = 36
\]

Now add these two results:

\[
\text{Weighted Average} = 3 + 36 = 39
\]

Thus, the weighted average is \( \boxed{39} \).