How many kg of sugar costing ₹ $11.70/kg$ must be mixed with $24$ $kg$ of sugar costing ₹ $8.1/kg$ so that there may be a gain of $15 \%$ by selling the mixture at ₹ $9/kg$? (in $kg$)

In what ratio should coffee powder costing ₹ $2500$ per $kg$ be mixed with coffee powder costing ₹ $1500$ per $kg$ so that the cost of the mixture is ₹ $2250$ per $kg$?

$200$ litres of mixture contains $15 \%$ water and the rest is milk. The amount of milk that must be added so that the resulting mixture contains $87.5 \%$ milk is..........$Litre$

$A$ mixture of milk and water measures $60 \, ltr$. It contains $20 \%$ water. How many litres of water should be added to it so that water may be $25 \% $ (in $ltr$)?

$A$ bottle full of whisky contains $50 \%$ alcohol. $A$ part of this whisky is replaced by another containing $18 \%$ alcohol and the percentage of alcohol was found to be $26 \%$. The quantity of whisky replaced is

The ratio in which tea costing $Rs. 192$ per $kg$ is to be mixed with tea costing $Rs. 150$ per $kg$ so that the mixed tea,when sold for $Rs. 194.40$ per $kg$,gives a profit of $20\%$,is: