If the given two numbers are respectively $7 \%$ and $28 \%$ of a third number,then what percentage is the first of the second?

Two numbers are $90 \%$ and $75 \%$ lesser than a third number. By what percentage should the first number be increased so that it becomes equal to the second number?

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

In a class,$60 \%$ of the students pass in Hindi and $45 \%$ pass in Sanskrit. If $25 \%$ of them pass in both subjects,what percentage of the students fail in both subjects?

In an examination in which full marks were $800,$ $A$ gets $20 \%$ more than $B,$ $B$ gets $20 \%$ more than $C,$ and $C$ gets $15 \%$ less than $D.$ If $A$ got $576,$ what percentage of full marks did $D$ get (approximately) (in $\%$)?

Rita invested $25 \%$ more than Sunil. Sunil invested $30 \%$ less than Abhinav,who invested $Rs$ $6,000$. What is the ratio of the amount that Rita invested to the total amount invested by all of them together?