Jonathan S. answered • 10/14/15
Certified, Experienced Tutor and Teacher – Physics, Math, SATs
First, find the total area of the vegetable garden by multiplying its length by its width: 8 ft × 13 ft = 104 sqft. We need to find how many bags of 12 sqft of fertilizer per bag will be needed to cover 104 sqft of land. We can express this sentence algebraically by naming our unknown value (number of bags) with a variable. Let's choose n. The word "of" tells us to multiply, and the word "is" usually can be replaced with an equals sign. What is the number of bags of fertilizer (n) of (×) (12 sqft/bag) that is needed to (=) (104 sqft) n × (12 sqft/bag) = (104 sqft) To get the variable n by itself, we must divide both sides by (12 sqft/bag). n = (104 sqft) ÷ (12 sqft/bag) Solving this expression tells us our answer. n = 8.67 bags. But wait! Depending on the specific wording of the question, there may be something saying that we should only deal with whole numbers of bags (Maybe it says, "How many bags should you buy?") In this case, knowing that in the real world, it is usually impossible to buy two-thirds of a bag of fertilizer, we should round up our number. It's better to buy a little extra fertilizer than not enough. n = 9 bags.
