X= 4A weighted average multiplies each data point by an arbitrary 'weight' and divides by the sum of the weights. Your everyday garden variety average, or arithmetic mean, is actually a special case of a weighted average, except all the weights are equal to 1.
Y = 8
AV = 6
4---6---8
Notice the distance to average from both sides are the SAME (2)
Now let's find the average of 4, 4, 4, 8
AV = 20/4=5
4..5........8
Now if you notice the distance between 4 and AVERAGE is 1 and the distance between 8 and AVERAGE is 3
since we used 3 fours our average shifted close to the 4.
if you compare the distances
4...L...5....3L.....8
L/3L = 1/3 gives us the weights of the each term in a reverse proportion:
from this distance information you can conclude
3 fours
1 eight
Play around with this concept and you will find it very useful in many mixture and average questions.
Happy studying,
LGTCH
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"DON'T LET ANYONE STEAL YOUR DREAM!"
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"DON'T LET ANYONE STEAL YOUR DREAM!"
