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 7 hours of burning, a candle has a height of 2

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Question 824129: 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 7 hours of burning, a candle has a height of 22.8centimeters. After 21 hours of burning, its height is14.4 centimeters. What is the height of the candle after 12 hours?
Found 2 solutions by josgarithmetic, dobear18:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
This same question has occurred a few weeks ago.

Identify two data points (x, y). Since the description indicates the function to be height of the candle, use x as burn time, and y as height. The two points then are (7, 22.8) and (21, 14.4).

We want y=mx+b equation form.
m=%2814.4-22.8%29%2F%2821-7%29=-8.4%2F14=highlight%28-3%2F5%29
Rearranging to have b,
b=y-mx
Use EITHER identified point
b=14.4-%28-3%2F5%2921=14.4%2B%283%2F5%2921=highlight%2827%29
'
The equation for height versus burn time is highlight%28y=-%283%2F5%29x%2B27%29.

Your objective to finish is find y when x=12.

Answer by dobear18(1) About Me  (Show Source):
You can put this solution on YOUR website!
I got 19.8 Can someone confirm.