He posts two products for selling price of $10 each product.
It says 3000 people buy both products, so sales would be = 2 x 3000 = 6000 items.
Another 4500 people buy only one product, so sales would be 4500 items.
So total sales would be sum of 6000 items and 4500 items.
Total sales = 6000 + 4500 = 10,500 items.
Sale price = $10 per item.
Total Earnings = (Sale price) x (Total sales)
Total Earnings = 10 x 10,500
Total Earnings = 1,05,000 dollars.
Hence, Carl will make $1,05,000 from this success.