CAT 2020 Exam Shift 1 Solved Paper

Original quantity of dye and water in the original solution i.e., 16 litres (i.e. $=40\times \frac{2}{5})$ and 24 litres (i.e. $=40-16$ )
Quantity of water added $=16$ litres (As 1 part $=8$ litres). Quantity of dye and water removed $=\frac{1}{4}\times \frac{2}{7}\left(56\right)$ i.e., 4 litres and $\frac{1}{4}\times \frac{5}{7}\times \left(56\right)$ i.e., 10 litres. Final quantity of dye and water is 12 litres and 30 litres.
$\therefore$ Quantity of dye to be added to make the ratio of dye and water again $2:3$ i.e., 8 litres.