Question

Dustin bought a dvd player that was markrd doen from 150 to 100 find the percent of decrease

Answer 1

It was 150, went down to 100, so it went 50 bucks.

now, if we take 150 as the 100%, what is 50 off of it in percentage?

$\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 150&100\\ 50&p \end{array}\implies \cfrac{150}{50}=\cfrac{100}{p}\implies p=\cfrac{50\cdot 100}{150}$