Answer:
To find out which cake is the most expensive per serving, we need to calculate the cost per serving for each cake.
The first cake serves 2 people and costs $4.50. So the cost per serving is:
$4.50 ÷ 2 = $2.25 per serving
The second cake serves 8 people and costs $10.00. So the cost per serving is:
$10.00 ÷ 8 = $1.25 per serving
The third cake serves 10 people and costs $20.00. So the cost per serving is:
$20.00 ÷ 10 = $2.00 per serving
Therefore, the first cake is the most expensive per serving, at $2.25 per serving.