Question

the price of a gallon of unleaded gas was $2.86 yesterday. today, the price fell to $2.79. find the percent decrease. round answer to the nearest tenth of a percent

Answer 1

so.. 2.86 - 2.79 is the amount in decrease or 0.07

so.. if we take 2.86 as the 100%, how much is 0.07 of that in percentage?

well $\bf \begin{array}{ccllll} amount&\%\\ \textendash\textendash\textendash\textendash\textendash\textendash&\textendash\textendash\textendash\textendash\textendash\textendash\\ 2.86&100\\ 0.07&x \end{array}\implies \cfrac{2.86}{0.07}=\cfrac{100}{x}$

solve for "x"