Final answer:
Deal B, at Costco, is the better deal because it offers 75 cupcakes for $30 with no discount, compared to Deal A at Walmart, which offers 50 cupcakes for $27 with a 10% discount.
Step-by-step explanation:
To determine which is a better deal, we need to compare the total number of cupcakes and their price after the discount. Deal A at Walmart offers 50 cupcakes for $30, but with a 10% discount, the total price becomes $27.
Deal B at Costco offers 50% more cupcakes than Deal A, which means it provides 75 cupcakes. However, the price remains $30, with no discount.