Final answer:
The cost of the caramel sauce on one banana split is $0.16.
Step-by-step explanation:
To calculate the cost of caramel sauce for one banana split, we need to divide the total cost of 2 containers of caramel sauce by the number of banana splits it can make.
Given that one container makes 20 banana splits, the total cost is $6.40 for 2 containers.
To find the cost per banana split, we divide the total cost by the number of banana splits: $6.40 ÷ 40 = $0.16 per banana split.
Therefore, the cost of the caramel sauce on one banana split is $0.16.