SOLUTION: If the average of x,y,z,and 90 is 20 less than the average of y,z,w,and 100, what is the value of w - x?

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Question 1132992: If the average of x,y,z,and 90 is 20 less than the average of y,z,w,and 100, what is the value of w - x?
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39617) About Me  (Show Source):
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The average of x, y, z, and 90 is %28x%2By%2Bz%2B90%29%2F4.

The average of y, z, w, and 100 is %28y%2Bz%2Bw%2B100%29%2F4.

The problem tells us that the first average is 20 less than the second average:

%28x%2By%2Bz%2B90%29%2F4+=+%28y%2Bz%2Bw%2B100%29%2F4+-+20

x%2By%2Bz%2B90+=+y%2Bz%2Bw%2B100+-+80

Combine terms where possible and cancel terms that are identical on both sides of the equation and see if you can see how to get the answer from there.

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Note: the solution by tutor @josgarithmetic contains errors and shows the wrong answer....

Can you see the two errors in that solution?