Joe's bathroom floor is 5 feet wide and 8 feet long. He will cover the floor with 3 - inch square tiles. How many tiles does he need?

So first find area

area=legnth times width

5=width

8=legnth

5 times 8=40

area=40

3 area times x number of tiles=40

divide both sides by 3

x=40/3

x=13 and 1/3

since you can't buy 1/3 tiile

round up

x=14

answer is 14