CAT (QA) PYQs

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

If a certain weight of an alloy of silver and copper is mixed with $3$ kg of pure silver, the resulting alloy will have $90\%$ silver by weight. If the same weight of the initial alloy is mixed with $2$ kg of another alloy which has $90\%$ silver by weight, the resulting alloy will have $84\%$ silver by weight. Then, the weight of the initial alloy, in kg, is

A jar contains a mixture of $175 \mathrm{ml}$ water and $700 \mathrm{ml}$ alcohol. Gopal takes out $10 \%$ of the mixture and substitutes it by water of the same amount. The process is repeated once again. The percentage of water in the mixture is now