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,
In comparison, $42.95 is lesser than $43.20.
Therefore, Keith got the better deal at $42.95.