Answer: $3.50
Explanation:
Let the cost of domestic shipping be x.
Since the cost of international shipping is $2.50 greater than the cost of domestic shipping. This will be:
= x + 2.50
Since we are further told that three of the cards will be shipped domestically, and two will be shipped internationally and that $22.50 will be spent on shipping, this will be express in an equation as:
3x + 2(x + 2.50) = 22.50
3x + 2x + 5.00 = 22.50
5x = 22.50 - 5.00
5x = 17.50
x = 17.50/5
x = $3.50
The cost if domestic shipping is $3.50