Given:
a.) Tony bought a 48$ sweatshirt and used a coupon for 10% discount.
b.) Keith bought an identical sweatshirt at a different store for $42.95.
To be able to determine who among them got the better deal, let's determine how much the sweatshirt Tony bought after a discount of 10%.
We get,
[tex]\text{Cost of Sweatshirt Tony bought = \$48 (}\frac{\text{100\% - Percent Discount}}{100}\text{)}[/tex][tex]\text{ = \$48 (}\frac{100\text{\% - 10\%}}{100})[/tex][tex]\text{ = \$48 (}\frac{90\text{\%}}{100})\text{ = \$48 (0.90)}[/tex][tex]\text{Cost of Sweatshirt Tony bought = \$4}3.20[/tex]In comparison, $42.95 is lesser than $43.20.
Therefore, Keith got the better deal at $42.95.