Since we want the percentage that he saved, we have to identify the amount it saved and the total initial amount.
Since the amount reduced from $90 to $75, the initial amount was $90 and the reduction was a total of:
[tex]90-75=15[/tex]Thus, the percentage is the ratio between the reduction and the total:
[tex]\frac{15}{90}=0.1666\ldots\approx0.1667=16.67\%[/tex]So, the amount he saved is approximately 16.67%.
