?qt of 100% antifreeze: ? of 50% 50%mix

my car recommends that a 80%antifreeze and20%water mix be used in the cooling system how many quarts of pure(100%)antifreeze and 50% antifreeze and 50% of water mix should be combined to make 11 quarts of 80% antifreeze and 20% water mix? ?qt of 100% antifreeze: ? of 50%_50%mix

429 qt of 100% antifreeze; − 418 qt of 50% −50% mix