Question

If a downpayment of $400 is 5% of the purchase price of a car, what is the purchase price

Answer 1

well, the purchase price is really "x", which oddly enough is the 100%, now, we know that $400 is 5% of that, so

`\begin{array}{ccll} Amount&\%\\ \cline{1-2} x & 100\\ 400& 5 \end{array} \implies \cfrac{x}{400}~~=~~\cfrac{100}{5} \\\\\\ \cfrac{x}{400} ~~=~~ 20\implies x=8000`