Easy, you must multiply 3.50 by 2.40 to get a product of $8.40 for three and a half dozen!! All of this is because $2.40 for 12 bagles so first you multiply 2.40 by 3.00 to get 7.2 then you must multiply 0.5 by 2.40 to get 1.2 then add that to your previous answer to then get a final answer of $8.40!!