SOLUTION: Suppose that the height (in centimeters) of a candle is a linear function of the amount of time (in hours) it has been burning. After 12 hours of burning, a candle has a height of

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Suppose that the height (in centimeters) of a candle is a linear function of the amount of time (in hours) it has been burning. After 12 hours of burning, a candle has a height of       Log On


   

Question 1148980: Suppose that the height (in centimeters) of a candle is a linear function of the amount of time (in hours) it has been burning. After 12 hours of burning, a candle has a height of 14.8 centimeters. After 29 hours of burning, its height is 4.6 centimeters. What is the height of the candle after 21 hours?
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Points (x,y) for time and height
(12,14.8) and (29,4.6);
What is y when x is 21 ?

y-14.8=%28%284.6-14.8%29%2F%2829-12%29%29%28x-12%29

y=%28%28-10.2%29%2F%2817%29%29%28x-12%29%2B14.8
y=-0.6%28x-12%29%2B14.8
y=-0.6x%2B7.2%2B14.8
highlight_green%28y=-0.6x%2B22%29----------------substitute 21 for x, and evaluate.