Hi Connie,

Your cost was $\$0.70$ and your selling price was $\$3.75$ so your profit is $\$3.75 - \$0.70 = \$3.05.$ You can express your profit as a percentage in two different ways.

To express the profit as a percentage of your cost divide the profit $(\$3.05)$ by your cost $(\$0.70)$ and multiply by $100.$ That is

\[\frac{\$3.05}{\$0.70} \times 100 = 436\%\]

This is sometimes called the markup.

To express the profit as a percentage of your selling price divide the profit $(\$3.05)$ by your selling price $(\$3.75)$ and multiply by $100.$ That is

\[\frac{\$3.05}{\$3.75} \times 100 = 81\%\]

This is sometimes called the margin.

I hope this helps,
Penny