A scientist suggests keeping indoor air relatively clean as follows: provide 2 or 3 pots of flowers for every 100 square feet of floor space under a ceiling of 8 ft. If your classroom has an 8 ft ceiling and measures 35 ft by 40 ft, how many pots should it have?
First we calculate classroom surface: 35*40=1400 square ft we know that for every 100 square ft 2 or 3 pots can be put so 1400/100=14 14*2=28 14*3=42 we need 28 or 42 pots