How much of pure (100%) orange juice must be added to 35 gallons of a 21% orange juice solution to obtain a 78% orange juice solution?

Diphenhydramine HCL is an antihistamine available in liquid form, part medication and part water. One formulation contains 16 mg of medication in 5 mL of liquid. An allergist orders 40-mg doses for a high school student. How many milliliters should be in each dose?

My car can travel 150 miles with a full gas tank. Now the deposit has 2/6 of the total. How many kilometers have I traveled? How many more kilometers can I travel on the gasoline I have left?

3. A 2% saline solution is to be combined and mixed with a 6% saline solution to produce 2.25L of a 2.75% saline solution. How much of each is needed?