A candle of 10 cm long burns at the rate of 4 cm in 4 hours and another candle of 12 cm long burns at the rate of 10 cm in 5 hours. If both the candles start burning at the same time; after how long will they be of same length.
Explanation:
Burning rate of 10 cm long candle = 4/4 = 1 cm/hr.
Burning rate of 12 cm long candle = 10/5 = 2 cms/hr.
Let the candles be of equal length after t hours.
∴ 10 – t × 1 = 12 – t × 2
⇒ t = 2 hours.
∴ It will takes 2 hours for the two candles to become equal in length.
Hence, option (c).
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