Question

Fawzia just lit a new candle and then let it burn all the way down to nothing. Thecandle burned at a rate of 1.5 inches per hour and its initial length was 15 inches.Make a table of values and then write an equation for L, in terms of t, representingthe length of the candle remaining unburned, in inches, t hours after the candle waslit.

Answer 1

Given:

Fawzia just lit a new candle and then let it burn all the way down to nothing. The

candle burned at a rate of 1.5 inches per hour and its initial length was 15 inches.

Required:

To write the equation.

Explanation:

Now make a table

Number of hours Length of the candle remaining

0 15

1 13.5

2 12

3 10.5

Here the general foem of equation is

$L=mt+b$

Where m is the slope

$\begin{gathered} m=\frac{13.5-15}{1-0} \\ \\ =\frac{-1.5}{1} \\ \\ =-1.5 \end{gathered}$

Now the equation is

$L=-1.5t+b$

Now we have to find the value of b, by consider (0,15)

$\begin{gathered} 15=0+b \\ b=15 \end{gathered}$

Now the equation is

$L=-1.5t+15$

Final Answer:

$L=-1.5t+15$