A scientist has a 35% solution of HCl (hydrochloric acid) and a 5% solution of HCL. How much of each solution should the scientist use to get 30L of a 20% solution of HCl?

Jake bakes and sell apple pies. he sells each pie for $5.75 . the materials to make the pies cost $40. the boxes jake puts the pies in cost & 12.50 total. how many pies does jake need to sell to earn a profit of $50