Answer:
4 layers with $2.84 left over
Explanation:
You start off with the cost of the cake which is $12.96, then add $3.55 (in this case 4 times) until you get the closest number to $30 without going over ($27.16) . You find the amount of money that is left over by subtracting you original amount ($30) with the amount you spent total on the cake ($27.16) .