If $10 \%$ of $x$ is $3$ times $15 \%$ of $y,$ then find $x: y.$

In a class of $80$ students and $5$ teachers,each student received sweets equal to $15 \%$ of the total number of students,and each teacher received sweets equal to $25 \%$ of the total number of students. How many sweets were there in total?

When a number is divided by $12$,the quotient becomes $1/4$ of another number. By what percentage is the first number greater than the second number?

Pooja invests $13 \%$ of her monthly salary,i.e.,$Rs. 8554$ in Mediclaim Policies. Later she invests $23 \%$ of her monthly salary on Child Education Policies,she also invests another $8 \%$ of her monthly salary on Mutual Funds. What is the total annual amount invested by Pooja?

Deepti invests $11 \%$ of her monthly salary,i.e.,$Rs. 5236$ in Fixed Deposits. Later she invests $19 \%$ of her monthly salary on Life Insurance Policies; also she invests another $7 \%$ of her monthly salary on Mutual Funds. What is the total annual amount invested by Deepti?

$A$ sum of $Rs$ $7,930$ is divided into $3$ parts and given on loan at $5 \%$ simple interest to $A, B$ and $C$ for $2, 3$ and $4$ years respectively. If the amounts (principal + interest) of all three are equal after their respective periods of loan,then the amount $A$ received as a loan is: