
### Instruction: help me answer this question (5.1) A solution of 8% boric acid is to be diluted by adding a 2% boric acid solution to it. The resulting mixture is to be more than 4% but less than 6% boric acid. If we have 640 litres of the 8% solution, how many litres of the 2% solution will have to be added?, think step by step
### Assistant:  , The answer is The number of litres of 2% of boric acid solution that has to be added will be more than 320 litres but less than 1280 litres.
