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?

Sweta invested $Rs. 10,000$ in a scheme exactly three years ago. The value of the investment increased by $10\%$ during the first year,increased by $5\%$ during the second year,and decreased by $10\%$ during the third year. What is the value of the investment today?

The length and breadth of a square are increased by $30 \%$ and $20 \%,$ respectively. The area of the rectangle so formed exceeds the area of the square by:

$A$ student has to secure $15\%$ marks to pass the examination. If he gets $80$ marks and fails by $70$ marks,find the maximum marks set for the examination.

$25 \%$ of $25 \% = ?$

Two litres of water evaporate from $10$ litres of a solution containing $10 \%$ salt. The percentage of salt in the remaining solution is