To find the total cost \( c \) that Vicky paid for the 3 1/2 pounds of oranges at a cost of $3.90 per pound, you can represent this situation with the following equation:
\[ c = 3.90 \times 3.5 \]
Calculating this gives:
\[ c = 3.90 \times 3.5 = 13.65 \]
So, the correct way to represent the total cost is:
\[ c = 3.90 \cdot 3.5 \]
Therefore, the equation representing the total cost, \( c \), is:
\[ c = 3.90 \times 3.5; \quad \text{Vicky paid } $13.65. \]
In your provided options, the correct representation would likely be:
Start Fraction c over 3.5 End Fraction equals 3.90 ; Vicky paid $13.65.
However, that isn't exactly correct because \( c \) should be multiplied by 3.5, but it's the closest alignment with the total cost representation.
So, the format matching your options isn't ideal, but remember \( c = 3.90 \times 3.5 \) is the key equation leading to a total cost of $13.65.