To answer this question you will find out the total number of cupcakes donated and then calculate the amount of each flavor based on the percentage that is stated.
Here are the steps:
1. 12 x 10 x 12 (12 classes each donating 10 dozen) = 1440
2. 0.55 x 1440 (55% are chocolate) = 792 chocolate
3. 1440 - 792 (the remaining number of cupcakes)=648
4. 1/3(33 1/3%) x 648 = 216 red velvet
5. 1440 - 792 (chocolate) - 216 (red velvet) = 432 vanilla cupcakes
Chocolate-792
Red velvet - 216
Vanilla - 432