2025 SSMO Accuracy Round Problems/Problem 3

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Problem

Nonnegative real numbers $x,y,$ and $z$ satisfy \[\frac{\sqrt{x}+13}{y} = \frac{\sqrt{y}+29}{z} = \frac{\sqrt{z} + 46}{x} = 2\] and \[\frac{\sqrt{x} + \sqrt{y}+\sqrt{z}}{x+y+z} = \frac{6}{25}.\] Find the value of $x+y+z$.

Solution

From the first chain of equalities in the problem statement, when we clear any appearing fractions, we have \begin{align*} \sqrt{x} &= 2y - 13 \\ \sqrt{y} &= 2z - 29 \\ \sqrt{z} &= 2x - 46. \\ \end{align*} Adding these three equations together, we obtain \[\sqrt{x}+\sqrt{y}+\sqrt{z} = 2(x+y+z) - 88.\] Plugging this into the last equation in the problem statement, we have \[\frac{2(x+y+z)-88}{x+y+z} = \frac{6}{25}.\] It is straightforward to solve this equation for $x+y+z$; we find that $x+y+z = \boxed{50}$.

~Sedro