Question

The value of a professional basketball player's autograph rose 20% in the last year. It is now worth $312.00. What was it worth a year ago?

Answer 1

well, let's say it was "x", so that's the 100% then. 312 is today's price, which is 20% more than last year's, therefore 312 is really 100% + 20% or 120%.

if 312 is the 120%, what is "x" anyway?


`\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 312&120\\ x&100 \end{array}\implies \cfrac{312}{x}=\cfrac{120}{100}\implies \cfrac{312\cdot 100}{12}=x`