SOLUTION: A candle is lit and the length of the burning candle changes at a constant rate of -1.8 inches per hour. 3 hours after the candle was lit the candle was 8.7 inches long. Determi

Algebra ->  Expressions-with-variables -> SOLUTION: A candle is lit and the length of the burning candle changes at a constant rate of -1.8 inches per hour. 3 hours after the candle was lit the candle was 8.7 inches long. Determi      Log On


   

Question 1133813: A candle is lit and the length of the burning candle changes at a constant rate of -1.8 inches per hour. 3 hours after the candle was lit the candle was 8.7 inches long.
Determine how long the candle was before it was lit.
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Equation for the line of slope -1.8 containing point (3, 8.7);
and question asks for y-intercept.

y-8.7=-1.8%28x-3%29
y=-1.8%28x-3%29%2B8.7
y=-1.8x%2B5.4%2B8.7
y=-1.8x%2B14.1

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


At 1.8 inches per hour, the candle loses 3*1.8 = 5.4 inches in 3 hours.

If the candle is 8.7 inches long after 3 hours, then its original length was 8.7+5.4 = 14.1 inches.