Stepby-step explanation: 4 cans for 3 dollars. Since this only costs <em><u>1$ more than</u></em> the possible prices of the <em><u>4 cans</u></em> then that's the answer.
In shorter terms; it's like 1 can cost 2 dollars on the 3 for 4 deal, and 1 can cost 3 dollars on the 9 for 12 deal, find this out by subtracting 9 from 12 and subtracting 3 from 4
