To find the square footage of a room you just take the length multiply it by the width and that's your square feet. now you divide that by 9 to get the square yards.
15 by 14 is 210 Sq ft which is 23.33 yards If installation is 5$ a yard Pad is 3$ a yard. Carpet you get a 12 $ a yard carpet (med. Grade) So right at about 500$ is what you'd be looking at