A rectangular room measures 12ft by 15ft. the entire room is to be covered with rectangular tiles that measures 5in by 4in. if the tiles are sold for &2.50 a dozen what will it cost to tile the room?

To answer this problem, you need to find the area of the room, but it cannot be in square feet, rather in square inches. Because there are 12 inches in 1 foot, convert the dimensions to inches.

Now that the dimensions are in inches, we can find the area in square inches. For a rectangle, the equation for area is:

Therefore the area of the room is as followed:

Now that we know the area of the room is 25920 square inches, we need to find the area of each tile by using the same area formula:

Now we need to find how many tiles can fit into the area of the room. Since there are 25920 square inches to fill and there are 20 square inches per tile, we divide the area of the room by the area of each tile.

Now we know that 1296 tiles are needed to fill the entire room. Since the tiles are sold in dozens (or sets of 12), we divide the number of tiles by 12 to get how many dozens are needed to fill the room

Now we know we need to purchase 108 sets of tiles at $2.50 each so we multiply 108 and 2.50 to get our final answer.