Step 1: Find what the price is per muffin. To do this you must divide $3.00 by 3 muffins (this will tell you dollar per muffin or $/muffin)
3 ÷ 3 = 1
This means that every muffin is $1
Since we know this, and we know that a dozen means 12 we can multiply 1 by 12 to find how much you would pay for a dozen muffins
12 × 1 = 12
It's $12 per dozen muffins
Hope this helped!