CAT (QA) PYQs

A trader sells $10$ litres of a mixture of paints $A$ and $B$, where the amount of $B$ in the mixture does not exceed that of $A$. The cost of paint A per litre is Rs. $8$ more than that of paint B. If the trader sells the entire mixture for Rs. $264$ and makes a profit of $10 \%$, then the highest possible cost of paint B, in Rs. per litre, 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

There are four bottles. It is known that either one or two of these bottles contain(s)only P, while the remaining ones contain 85% P and 15% I. What is the minimum number of tests required to ascertain the exact number of bottles containing only P?