An alloy contains copper,zinc and nickel in the ratio of $5: 3: 2$. The quantity of nickel in $kg$ that must be added to $100\, kg$ of this alloy to have the new ratio $5: 3: 3$ is

In what ratio must a person mix three kinds of wheat costing $Rs. 1.20$,$Rs. 1.44$ and $Rs. 1.74$ per $kg$ so that the mixture may be worth $Rs. 1.41$ per $kg$?

$A$ pot contains $81$ $\text{litres}$ of pure milk. $\frac{1}{3}$ of the milk is replaced by the same amount of water. Again $\frac{1}{3}$ of the mixture is replaced by that amount of water. The ratio of the milk and water in the new mixture is?

$A$ mixture contains wine and water in the ratio $3:2$ and another mixture contains them in the ratio $4:5$. How many litres of the latter must be mixed with $3 \, L$ of the former so that the resulting mixture may contain equal quantities of the wine and water? (in $L$)

$A$ person has $60$ pens. He sells some of these at a profit of $12 \%$ and the rest at $8 \%$ loss. On the whole,he gets a profit of $11 \%$. How many pens were sold at $12 \%$ profit and how many at $8 \%$ loss?

$A$ trader has $50 \text{ kg}$ of pulses,part of which he sells at $8 \%$ profit and the rest at $18 \%$ profit. He gains $14 \%$ on the whole. What is the quantity sold at $18 \%$ profit? (in $\text{kg}$)