Question { Zoho, 5859 }

Raja was studying for his examinations and the lights went off. It was around 1:00 AM. He lighted two uniform candles of equal length but one thicker than the other. The thick candle is supposed to last six hours and the thin one two hours less. When he finally went to sleep, the thick candle was twice as long as the thin one. For how long did Raja study in candle light?

Answer

3 Hr is the Answer
Thick can last for 6hr. Thin can last for 4 hr. Let LCM of 6,4 be the total length of candle. Candle Length = 12
Hence, their efficiency ratio is
Th : Tn = 2 : 3 (In 1hr, 2 parts of Thick candle and 3 parts of thin candle Burnt down)
Hence in 3 hr, 6 parts of Thick candle and 9 parts of Thin candle burnt down
Remaining 6 parts of Thick candle and 3 parts of Thin candle is there Out of 12 parts(It is of ratio 2 : 1)
Hence 3 hr is the answer