If the owner is giving a free cupcake to every 4th customer. Then the easiest way to do this is to follow the 4 times table: 4, 8, 12, 16, 20
So the answer is No, Emma will not be receiving a free cupcake as she is the 17th customer and doesn't fall into the 4th customer pattern.
7/10-3/10=2/5
3/10+1/10=2/5
Letter A is the answer to your equation problem
