$40 \%$ of $1640 + ? = 35 \%$ of $980 + 150 \%$ of $850$

The number of students in a class is increased by $20 \%$ and the number now becomes $66$. Initially,the number was:

$65 \%$ of $? = 20 \%$ of $422.50$

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?

The population of a town increases $4 \%$ annually but is decreased by emigration annually to the extent of $(1/2) \%$. What will be the increase per cent in $3$ years?

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?