Final answer:
To calculate the total cost of Emmett's frozen yogurt sundae, we define variables representing the number of each type of topping he selects. The variable 'f' indicates the number of fruit toppings, while 'c' stands for the number of candy toppings, allowing for an easy calculation of the total cost.
Step-by-step explanation:
Emmett is ordering a frozen yogurt sundae, and variables will be necessary to calculate the total cost based on his selections. In this situation, we can define two variables: f represents the number of fruit toppings Emmett chooses, and c represents the number of candy toppings. Since each fruit topping costs $1.25, the total cost for fruit toppings would be 1.25f. Similarly, since each candy topping costs $0.75, the total cost for candy toppings would be 0.75c. Therefore, the total cost of Emmett's sundae can be represented as 3.25 + 1.25f + 0.75c, where $3.25 is the cost of one scoop of regular frozen yogurt.