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Two candles of equal height but …

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Two candles of equal height but different thickness are lightened. The first burns off in 6 hours and the second one in 8 hours. How long after lightning booth, will first candle be half the height of second?
  • 1 answers

Sia ? 5 years, 11 months ago

Let height of each candle = x unit.
First candle burns off in 6 hours.
Second candle burns off in 8 hours.
Height of 1st candle after burning for 1 hr = x6unit
and height of 2nd candle after burning for 1 hr = x8unit
Let the required time =y hrs.
Length of 1st candle burnt after y hrs = y×x6unit
Height of 1st candle left = (xxy6)
Length of 2nd candle burnt after y hrs = (y×x8)unit
Height of 2nd candle left = (xxy8)
According to the question,
Height of 1st candle = 12×Height of 2nd candle
xxy6=12(xxy8)
x(1y6)=12x(1y8)
1y6=12(1y8)
2y3=1y8
21= y3y8
1 = 8y3y24
 24=5y
 y= 245
y=4.8hours=4 hours 48 minutes.

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