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Homework Help: Burning Candles

  1. Oct 31, 2008 #1
    1. The problem statement, all variables and given/known data

    Two candles A and B are 8cm and 14cm long, respectively, and are lit at hte same time. If candle B burns twice as fast as candle A, how long are they when their lengths are the same. How long is candle A when candle B burns out?

    2. Relevant equations

    Not sure.

    3. The attempt at a solution

    I drew a table of length's for equal time width's. So when A is 7cm ling B will be 12cm long etc. I found that they would be 2cm a piece when they are the same length and that candle A would be 1cm long when candle B burns out. Is this correct?

    More importantly how do I answer this question algebraically? The above seems to me like the dumb approach, but I just can't see how to model teh problem.

    Any help would be much appreciated!
  2. jcsd
  3. Oct 31, 2008 #2


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    Homework Helper

    Your answers are right. Let LB = Length Burned of A

    8 - LB = Height(a)

    14 - 2*LB = Height(b)

    When Heights are equal LB = 6, Height(a) = 2
    When Height(b) = 0, T = 7, then Height(a) = 8 - 7 = 1
  4. Oct 31, 2008 #3
    Thanks a million LowlyPion. I kept trying to use series sums etc, but I just couldn't get it to work. Your answer is much simpler!

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