Math
posted by Sara .
A rectangular room measures 15ft by 21ft. How much will it cost to carpet this room if carpeting costs $17.95 per square yard?

15 ft = 5 yards
21 feet = 7 yards
5 * 7 = 35 square yards
35 * 17.95 = ? 
15'x21'=315 square feet
315'/9 equals 35 square yards
HOWEVER most carpet no longer comes 15' wide, it comes 12'. Depending on the direction the sunlight comes in the room and where the bulk of the traffic flows into the room you have to decide where to place the fill seam, AND when measuring most people measure base to base, but you have to go THROUGH the doorways because the carpet will join the next rooms flooring under the door. So now we need 4' of fill (3' won't get it if we are accounting for the door way)so you would need 12x28'=336'/9=37.33 square yards x 17.95=$670.13
BUT if only the carpet costs $17.95 have you figured into the equation the price of padding and installation?
There is a lot that goes on in figuring out how much it will cost to carpet a room. 
$628.25

€638

29. What will it cost to carpet a rectangular floor measuring 15 feet by 21 feet if the carpet cost $22.50 per square yard?