By how many percent and how has the area of the rectangle changed, if one side

By how many percent and how has the area of the rectangle changed, if one side of the rectangle was increased: by 50%, and the other was reduced by 50%?

Let us denote the lengths of the sides of this rectangle through x and y.

Then the area S of this rectangle will be:

S1 = x * y.

If the first side of this rectangle is increased by 50%, and the second side of this rectangle is reduced by 50%, then the first side of the rectangle will be x + (50/100) x = 1.5x, and the second rectangle will be y – (50/100) y = 0.5y.

Then the area S2 of the resulting rectangle will be:

S2 = 1.5x * 0.5y = 0.75xy = 0.75 * S1.

Therefore, the area of ​​the original rectangle will decrease by:

100 * (S1 – 0.75 * S1) / S1 = 100 * 0.25 * S1 / S1 = 100 * 0.25 = 25%.

Answer: the area of ​​the rectangle will decrease by 25%.



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