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	\problem{An Elephant and a Mosquito}

	Does the weight of an elephant equal the weight of a mosquito? Let $x$ be the weight of an elephant, and $y$ that of a mosquito.

	\begin{figure}[h]
		\centering
		\includegraphics[width=10cm]{252}
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	Call the sum of the two weights $2v$, then $x + y = 2v$.

	From this equation we can obtain two more:

	\[
		x - 2v = -y \text{; } x = - y + 2v
	\]

	Multiply:
	\[
		x^2 - 2vx = y^2 - 2vy
	\]

	Add $v^2$:
	\[
		x^2 - 2vx + v^2 = y^2 - 2vy + v^2 \text{, or } (x - v)^2 = (y - v)^2
	\]

	Take square roots:
	\[
		x - v = y - v \text{; } x = y
	\]

	That is, the elephant's weight ($x$) equals the mosquito's weight ($y$). What is wrong here?


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