The weight of a container alone is $25 \%$ of the container filled with a certain fluid. When some fluid is removed,the weight of the container and remaining fluid is $60 \%$ of the original total weight. What fractional part of the liquid has been removed?

$A$ boy found the answer for the question "subtract the sum of $\frac{1}{4}$ and $\frac{1}{5}$ from unity and express the answer in decimals" as $0.45$. The percentage of error in his answer was

Two numbers $A$ and $B$ are such that the sum of $6\%$ of $A$ and $4\%$ of $B$ is two-thirds of the sum of $6\%$ of $A$ and $8\%$ of $B$. Find the ratio of $A:B$.

$A, B$ and $C$ start a business by investing $Rs. 70000$ that earns them a profit of $Rs. 42000$ at the end of the year. $A$ invests his share in the profit in a scheme that gives $10\%$ interest compounded annually and $B$ invests his share in a scheme that gives $20\%$ interest compounded annually. $A$ gets $Rs. 2520$ as interest at the end of $2$ years and $B$ gets an interest of $Rs. 4200$ at the end of one year. Find $C$'s investment in the business.

Rajeev buys goods worth Rs. $6650$. He gets a rebate of $6\%$ on it. After getting the rebate,he pays sales tax at the rate of $10\%$. Find the total amount he will have to pay for the goods.

In measuring the sides of a rectangle,one side is taken $10 \%$ in excess and the other $20 \%$ in deficit. Find the error per cent in area calculated from the measurement.