Question

a 9-inch candle burns down in 12 hours. at what rate does the candle burn, in inches per hour?

Explanation:

Step1: Identify the formula for rate

Rate is calculated as the amount of change (in this case, the length of the candle burned) divided by the time taken. So, the formula for the burning rate \( r \) is \( r=\frac{\text{length of candle}}{\text{time taken}} \).

Step2: Substitute the given values

The length of the candle is 9 inches and the time taken is 12 hours. Substituting these values into the formula, we get \( r = \frac{9}{12} \).

Step3: Simplify the fraction

Simplify \( \frac{9}{12} \) by dividing both the numerator and the denominator by their greatest common divisor, which is 3. So, \( \frac{9\div3}{12\div3}=\frac{3}{4} = 0.75 \).

Answer:

The candle burns at a rate of \( \frac{3}{4} \) (or 0.75) inches per hour.