[tex]x-number\ of\ skiers\\x+1250-numbers\ of\ snowboarders\\\\\frac{skiers}{snowboarders}=\frac{1}{2}\Rightarrow\frac{x}{x+1250}=\frac{1}{2}\ \ \ \ |cross\ multiply\\\\2x=x+1250\ \ \ \ \ \ |subtract\ x\ from\ both\ sides\\\\x=1250\\\\x+1250=1250+1250=2500\\\\Answer:There\ are\ 1250\ skiers\ and\ 2500\ snowboarders.[/tex]