SOLUTION: A poster advertising a student election candidate is too large according to the election rules. The candidate is told she must reduce the length and width of the poster by 20%. By

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Question 780126: A poster advertising a student election candidate is too large according to the election rules. The candidate is told she must reduce the length and width of the poster by 20%. By what percentage must the area of the poster be reduced?
The answer is 36%, I just do not know how to get there.
Answer by MathTherapy(10556) About Me  (Show Source):
You can put this solution on YOUR website!

A poster advertising a student election candidate is too large according to the election rules. The candidate is told she must reduce the length and width of the poster by 20%. By what percentage must the area of the poster be reduced?
The answer is 36%, I just do not know how to get there.

Let the length and width of the "too large" poster be L and W, respectively

Then its area = LW

Reducing its length, or L by 20% makes it 80% of its original length, or .8L

Reducing its width, or W by 20% makes it 80% of its original width, or .8W

New area with new, reduced length and width = .8L * .8W, or .64LW

It's obvious that the original area (LW) has been reduced to .64LW, which is a difference of LW - .64LW, or .36LW, or highlight_green%2836%29% of LW (area).