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Question

Two candles of the same height are lighted at the same time. The first is consumed in 4 hours and the second in 3 hours. Assuming that each candle burns at a constant rate, in how many hours after being lighted was the first candle twice the height of the second?

Accepted Answer

In x hours, the height of the first candle is 1 - x4 and the height of the second candle is 1 - x3 Essentially, we are solving the equation 1 - x4 = 2(1 - x3). - x4 = 1 - 2x3 | -1 - 3x = 12 - 8x | 12 5x = 12 | +8x x = 125 | /5 x = 225 hours.