CAT (QA) PYQs

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

A $20 \%$ ethanol solution is mixed with another ethanol solution, say, $S$ of unknown concentration in the proportion $1:3$ by volume. This mixture is then mixed with an equal volume of $20 \%$ ethanol solution. If the resultant mixture is a $31.25 \%$ ethanol solution, then the unknown concentration of $S$ is

From a container filled with milk, $9$ litres of milk are drawn and replaced with water. Next, from the same container, $9$ litres are drawn and again replaced with water. If the volumes of milk and water in the container are now in the ratio of $16: 9$, then the capacity of the container, in litres, is