Calvin is mixing colored gravel for the bottom of his fish tank. He mixes 12 pounds of blue gravel with 3 pounds of purple gravel. How much blue gravel is used per pound of purple gravel?

Answer 1

To find out how much blue gravel is used per pound of purple gravel, we can set up the ratio of blue gravel to purple gravel.

Calvin mixes:

• 12 pounds of blue gravel
• 3 pounds of purple gravel

The ratio of blue gravel to purple gravel is given by:

\[ \text{Ratio} = \frac{\text{Amount of blue gravel}}{\text{Amount of purple gravel}} = \frac{12 \text{ pounds}}{3 \text{ pounds}} \]

Now, we can simplify this ratio:

\[ \frac{12}{3} = 4 \]

This means that for each pound of purple gravel, there are 4 pounds of blue gravel used.

Therefore, the amount of blue gravel used per pound of purple gravel is \( \boxed{4} \).