$A$ scored $30\%$ marks and failed by $15$ marks. $B$ scored $40\%$ marks and obtained $35$ marks more than that required to pass. The pass percentage is: (in $\%$)

$A, B$ 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.

If $25 \%$ of a number is subtracted from a second number,the second number reduces to its five-sixths. What is the ratio of the first number to the second number?

If $A$'s salary is $40\%$ less than that of $B$,then how much percent is $B$'s salary more than that of $A$?

The radius of a sphere is increased by $10 \%$. The surface area increases by

In a History examination,the average for the entire class was $80$ marks. If $10 \%$ of the students scored $95$ marks and $20 \%$ scored $90$ marks,what was the average marks of the remaining students of the class?