A certain drug is made from only two ingredients: compound A and compound B. There are 5 milliliters of compound A used for every 4 milliliters of compound B. If a chemist uses 255 milliliters of compound A, how many milliliters of the drug will be made? ---------------------------------- 4:5 is the same as 4x:5x where 4x is compound A and 5x is compound B. --- Solve for "x": If amount of compound A is 4x = 255 x = 255/4 ------------------------------ Then amt of compound B is 5x = 5(255/4) = 318.75 ml =========================