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**Soroban** Hello, Rocher!

The first candle is consumed in 4 hours.

. . In one hour, $\displaystyle \frac{1}{4}$ iof the candle is gone.

. . In $\displaystyle x$ hours, $\displaystyle \frac{x}{4}$ of the candle is gone.

In $\displaystyle x$ hours, there will be: $\displaystyle \left(1 - \frac{x}{4}\right)$ of the candle left.

The second candle is consumed in 3 hours.

. . In one hour, $\displaystyle \frac{1}{3}$ of the candle is gone.

. . In $\displaystyle x$ hours, $\displaystyle \frac{x}{3}$ of the candle is gone.

In $\displaystyle x$ hours, there will be $\displaystyle \left(1 - \frac{x}{3}\right)$ of the candle left.

If the first candle is twice the height of the second candle,

. . we have: .$\displaystyle 1 - \frac{x}{4} \;=\;2\left(1 - \frac{x}{3}\right)$

Now solve for $\displaystyle x.$