The floor of a rectangular room will be tiled with square tiles that measure 3 inches on each side. The room is 109 inches long and 103 inches wide. How many tiles, including parts of tiles, are needed to complete the job?

A. 1,248 tiles
B. 1,247 tiles
C. 1,224 tiles
D. 1,295 tiles
I think it is A but I am not sure...

2 answers

109/3 = 36.3
103/3 = 34.3
So, assuming no partial tiles are used, the job needs

37*34=1258

Hmm. Not a choice. So, assuming the cut pieces can be used,

(109*103)/(3*3) = 1247.4, so A seems reasonable.
Your second assumption is correct, but it would be 1248 because 0.4 of a tile requires an extra tile. Basically, you found the total area and divided it by the area of one tile, which indeed did give you the number of tiles necessary to fill it up. And since you can't have 0.4 of a tile, an extra tile will be required