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

Options

A. more than `320` and less than `1000`
B. more than `160` and less than `320`
C. more than `320` and less than `1280`
D. more than `320` and less than `640`

Answer

(c )