Gina is buying juice, she needs 30 servings. At the store she can get 30 individual boxes for $21.99, or she can get 1/2 gallon cartons of juice. Each carton is $3.99 and contains 5 servings. Which is better to for Gina to buy?

It is better for Gina to buy the individual boxes for $21.99 rather than to buy Each carton for $3.99

To find the total amount for the 1/2 gallons, you 1st round $3.99 to $4 then you multiply 4 by 6 to get 24. This means she pays a total of $24 for the 1/2 gallons.

The reason that you multiply 4 by 6 is because you'd need 6 1/2 gallons to make 30 servings