Final answer:
The total cost for three cases of water, with each case priced at $6.80, is $20.40 after multiplication.
Step-by-step explanation:
The total cost of the three cases of water can be found by multiplying the price per case by the number of cases. The price per case of water is $6.80, and the student purchases three cases.
- Price per case: $6.80
- Number of cases: 3
We calculate the total cost by multiplying the two:
Total cost = Price per case × Number of cases
Total cost = $6.80 × 3
Total cost = $20.40
Therefore, the total cost of the three cases of water is $20.40.