Question

if 4/7 pound of fertilizer covers 87 square feet of ground, how much fertilizer in pounds is needed to cover 1 square foot of ground?

Answer 1

`\begin{array}{ccll} \stackrel{lbs}{fertilizer}&\stackrel{feet^2}{ground}\\ \cline{1-2} (4)/(7)&87\\[1em] x&1 \end{array}\implies \cfrac{~~ (4 )/(7 ) ~~}{x}~~ = ~~\cfrac{87}{1}\implies \cfrac{~~ (4 )/(7 ) ~~}{(x)/(1)}=87 \\\\\\ \cfrac{4}{7x}=87\implies \cfrac{4}{87}=7x\implies \cfrac{4}{609}=x`