In what ratio must oil at $Rs. 62$ per $kg$ be mixed with oil at $Rs. 72$ per $kg$ so that the mixture is worth $Rs. 64.50$ per $kg$?

Acid and water are mixed in a vessel $A$ in the ratio of $5:2$ and in the vessel $B$ in the ratio $8:5$. In what proportion should quantities be taken out from the two vessels so as to form a mixture in which the acid and water will be in the ratio of $9:4$?

Haresh earned ₹ $4000$ per month. From the last month,his income increased by $8\%$. Due to a rise in prices,his expenditure also increased by $12\%$ and his savings decreased by $4\%$. Find his increased expenditure and initial savings.

The milk and water in two vessels $A$ and $B$ are in the ratio $4:3$ and $2:3$ respectively. In what ratio should the liquids in both the vessels be mixed to obtain a new mixture in vessel $C$ containing half milk and half water?

How many $Kg$ of tea,worth ₹ $25$ per $Kg$,must be blended with $30 \ Kg$ of tea worth ₹ $30$ per $Kg$,so that by selling the blended variety at ₹ $30$ per $Kg$ there should be a gain of $10 \%$?

In a mixture of $25\, L$,the ratio of acid to water is $4: 1$. Another $3\, L$ of water is added to the mixture. The ratio of acid to water in the new mixture is