You are shopping for T-Shirts on your favorite site. You choose 3 shirts, and the site
tells you they will cost $15.50 each, and shipping will cost $12.60
The website then suggests you can save some money by buying a 4th shirt, because
the cost per shirt will reduce to $14.00 each, AND shipping will be free.
How much money will you save by buying 4 T-Shirts?
Your answer will be a positive decimal value. You do NOT NEED the $ sign.