Final answer:
To earn a profit of $600 with a profit of $20 per product, you need to sell 30 products.
Step-by-step explanation:
To calculate how many products you need to sell to earn a profit of $600, you first determine the profit per unit by subtracting the expenses from the selling price. The selling price is $100, and expenses are $80, so the profit per unit is $20 ($100 - $80). To find out how many units you need to sell to have a total profit of $600, you divide the desired profit by the profit per unit:
$600 / $20 = 30 units
You would have to sell 30 products to earn a profit of $600.