First, calculate what 50% of 57 is equal to. Then, add that quantity to 57 to find the sales price.
To find what 50% of 57 is equal to, multiply 57 by 50/100:
[tex]\frac{50}{100}\times57=28.5[/tex]Add 28.5 plus 57:
[tex]28.5+57=85.5[/tex]Therefore, the store charges $85.5 for the skis.