Problem: what quantity of water should be added to reduce 9 liters of 50 % acidic liquid to 30 % acidic liquid ?
Rationale: acid in 9 liters = 50 % of 9 = 4.5 liters suppose x liters of water be added . then 4.5 liters of acid in 9 + x liters of diluted solution 30 % of 9 + x = 4.5 27 + 3 x = 45 x = 6 liters answer is a
annotated_formula: subtract(divide(multiply(multiply(9, divide(50, const_100)), const_100), 30), 9)