Final answer:
Alice and Betty's costs for 1 pizza are $2 each, assuming they each want to buy 1 pizza.
Step-by-step explanation:
To calculate Alice and Betty's costs for 1 pizza, we need to know the price of the pizza and the number of pizzas they are buying. In the given information, it states that each personal pizza will cost $2. If we assume that they each want to buy 1 pizza, then the cost for each of them would be $2. However, if they are buying different amounts or sharing the cost, we would need more information to accurately determine their individual costs.