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

How many kilograms of sugar costing $Rs. 9$ per $kg$ must be mixed with $27\, kg$ of sugar costing $Rs. 7$ per $kg$ so that there may be a gain of $10\%$ by selling the mixture at $Rs. 9.24$ per $kg$?

In what proportion must pulses of $Rs. 70$ per $kg$ be mixed with pulses of $Rs. 45$ per $kg$ to get a mixture of $Rs. 60$ per $kg$?

Some amount out of ₹$7000$ was lent at $6 \%$ $p.a.$ and the remaining at $4 \%$ $p.a.$ If the total simple interest from both the fractions in $5$ $years$ was ₹$1600$,the sum lent at $6 \%$ $p.a.$ was (in ₹).

In what ratio must water be added to spirit to gain $10 \%$ by selling it at the cost price?

$729 \, ml$ of a mixture contains milk and water in the ratio $7:2$. How much more water is to be added to get a new mixture containing milk and water in the ratio $7:3$? (in $ml$)