Question

The price of gas dropped from $3.50 to $3.35. What was the percent decrease?

Answer 1

well, from 3.50 to 3.35 is just 15 cents difference, 3.50 - 3.35 = 0.15.

Now, if we take 3.50(origin amount) to be the 100%, what is 0.15 off of it in percentage?

`\begin{array}{ccll} Amount&\%\\ \cline{1-2} 3.50 & 100\\ 0.15& x \end{array} \implies \cfrac{3.50}{0.15}~~=~~\cfrac{100}{x} \implies 3.5x=15 \\\\\\ x=\cfrac{15}{3.5}\implies x=\cfrac{30}{7}\implies x\approx 4.29`