90% acid solution is diluted with water to make a solution 60% acid. When 3 gallons of water is added to dilute it again the solution becomes 40% acid. How much water was added to the solution at the first instance? How much 90% acid is available?

1. A 90% acid solution is diluted with water to make a solution 60% acid. When 3 gallons of water is added to dilute it again the solution becomes 40% acid. How much water was added to the solution at the first instance? How much 90% acid is available?

2. Chaeyoung is planning to improve her trail mix recipe by adding some chocolate chips. Her original trail mix costs Php430/500g, and she can afford to spend 70php/500g more for a more chocolate-y taste. If she buys chocolate chips at 250php/100g, how much more chocolate chips can she add to 500g of her original trail mix?