Sonu invested $10 \%$ more than Mona. Mona invested $10 \%$ less than Raghu. If the total sum of their investments is ₹$5,780$,how much amount did Raghu invest?

The length of a rectangle is increased by $30 \%$ and the breadth by $20 \%$. Then the perimeter of the rectangle will increase by what percent?

The average monthly salary of all the employees in a factory is $Rs$ $8840$. If the average salary of all the officers is $Rs$ $15000$ and that of the remaining employees is $Rs$ $8000$,then what is the percentage of the officers among the employees?

Six-elevenths of a number is equal to $22 \%$ of a second number. The second number is equal to one-fourth of a third number. The value of the third number is $2400$. What is $45 \%$ of the first number?

$A$ 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.

If one number is $80 \%$ of the other and $4$ times the sum of their squares is $656,$ then the numbers are: