If the ratio of chocolate to vanilla cupcakes is the same, that would make there 12 chocolate and 12 vanilla cupcakes. She means that she can use equivalent ratios by, lets say the grande box had 100 cupcakes, then we know 50 are chocolate. We don't know how many chocolate cupcakes that will be because we don't know how much bigger the bigger box of cupcakes is.
12... If there is an even ratio between the two, then there is an even amount, so you divide 24 by 2 and you have 12 chocolate and 12 vanilla cupcakes in the Grande box.
