SOLUTION: One candle will burn up completely in 4 hours, while a second candle of equal length requires 5 hours to burn up completely. If the candles are lit at the same time, how long will

Click here to see ALL problems on Miscellaneous Word Problems

Question 408976: One candle will burn up completely in 4 hours, while a second candle of equal length requires 5 hours to burn up completely. If the candles are lit at the same time, how long will they burn before one is exactly three times as long as the other?
Found 2 solutions by scott8148, ankor@dixie-net.com:
Answer by scott8148(6628) (Show Source):
You can put this solution on YOUR website!
3[1 - (x / 4)] = 1 - (x / 5)

3 - (3x / 4) = 1 - (x / 5)

multiplying by 20 (LCD) ___ 60 - 15x = 20 - 4x

40 = 11x ___ 40/11 = x

Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
One candle will burn up completely in 4 hours, while a second candle of equal
length requires 5 hours to burn up completely.
If the candles are lit at the same time, how long will they burn before one is
exactly three times as long as the other?
:
Assign a value to the length of the candles, 20"
then
= 5 in/hr burn rate of candle 1
and
= 4 in/hr burn rate of candle 2
:
let t = time for candle 2 to be 3 times candle 1
:
Candle 2 = 3 times candle 1
(20 - 4t) = 3(20 - 5t)
20 - 4t = 60 - 15t
-4t + 15t = 60 - 20
11t = 40
t =
t = 3 hrs; 3 + *60 = 38.2 min
:
3 hrs 38.2 min, Candle 2 will be three times the length of candle 1