1. **State the problem:** Amari bought 12 mini muffins for 5.40. We want to find out how many mini muffins Amari can buy with 4.00. 2. **Identify the formula:** We use the unit rate formula to find the cost per muffin and then use it to find the number of muffins for 4.00. 3. **Calculate the cost per muffin:** $$\text{Cost per muffin} = \frac{5.40}{12}$$ 4. **Simplify the fraction:** $$\frac{5.40}{12} = 0.45$$ So, each mini muffin costs 0.45. 5. **Find the number of muffins for 4.00:** $$\text{Number of muffins} = \frac{4.00}{0.45}$$ 6. **Simplify the division:** $$\frac{4.00}{0.45} = \frac{400}{45} = \frac{\cancel{5} \times 80}{\cancel{5} \times 9} = \frac{80}{9} \approx 8.89$$ 7. Since Amari cannot buy a fraction of a muffin, she can buy **8 mini muffins** with 4.00. **Final answer:** Amari can buy 8 mini muffins with 4.00.