To know the percentage of a quantity, we have to divide the percentage we want to know (in this case 80%), over 100%. Then, that part has to be multiplied by that result as it is the part that corresponds to 80%.
0. Dividing 80% over 100%
[tex]\frac{80}{100}=0.8[/tex]2. Multiplying by the quantity
[tex]0.8\times685=548[/tex]Answer: 548
