CAT (QA) PYQs

Bottle $1$ contains a mixture of milk and water in $7: 2$ ratio and Bottle $2$ contains a mixture of milk and water in $9: 4$ ratio. In what ratio of volumes should the liquids in Bottle $1$ and Bottle $2$ be combined to obtain a mixture of milk and water in $3: 1$ ratio?

A glass is filled with milk. Two-thirds of its content is poured out and replaced with water. If this process of pouring out two-thirds the content and replacing with water is repeated three more times, then the final ratio of milk to water in the glass, is

The strength of a salt solution is $p\%$ if $100 \mathrm{ml}$ of the solution contains p grams of salt. If three salt solutions $A, B, C$ are mixed in the proportion $1: 2: 3$, then the resulting solution has strength $20 \%$. If instead the proportion is $3: 2: 1$, then the resulting solution has strength $30 \%$. A fourth solution, $D$, is produced by mixing $B$ and $C$ in the ratio $2: 7$. The ratio of the strength of $D$ to that of $A$ is