Spending $12 on ingredients for 2 cakes, he spends 12 / 2 = $<<12/2=6>>6 on ingredients per cake.
Adding the cost of packaging, he spends 6 + 1 = $<<6+1=7>>7 per cake.
Selling each cake for $15, Andy's profit is 15 - 7 = $<<15-7=8>>8 per cake.
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