# Re: Length of Time

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Posted by MathBard on October 30, 2002 at 18:34:27:

In Reply to: Length of Time posted by RD on October 30, 2002 at 17:47:44:

: Two candles are in a building. One is red and the other is blue. The candles are the same height, but the red is slightly thicker. The red burns out in 3 hours and the blue 2. After an amount of time the length of the red left unburned was twice that of the blue. A person who was in the building had a watch but it stopped, and there was no other clock in the building. How long was the person there?

I bet Mr.G or Joel will do this more efficiently. and Dennis will make fun of it but..
let t= length of time
Blue "contains" 2 hours of life and red "contains" 3
so for as time passes we subtract from that
2-x is the time remaining in blue
3-x isthe time remaining in red after the "amout of time"
it tells that red had TWICe as much time left in it than blue so....
2(2-x)=3-x distribute
4-2x=3-x add 2x to both sides
4=3+x subtract 3 from both sides
1=x ONE hour
check it
after one hour red would have 2 hours of life left and blue would have 1 hour of life left THAT"S double!

Unless it is daylight savings time and they are on opposites sides of a timezone border (on a moving train)

MB

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