One kind of hard candy sells for 89 cent per kilogram. Another sells for $1.10

per kilogram. How many kilograms of each kind will be used for 30 kilograms of a mixture to sell for 96 cent per kilogram?

How many millileters of vinegar must be added to 20 milliters of a 10%-vineger solution to make it a 25% vinegar solution?

How would I solve these?