The population of Delhi increases by $10 \%$ every year. If the current population of Delhi is $1,331,000$,what was its population $3$ years ago?

$A$ man spends $75 \%$ of his income. His income increases by $20 \%$ and his expenditure also increases by $10 \%$. The percentage of increase in his savings is (in $\%$)

If $\frac{3}{5}$ of a number is $23$ more than $50 \%$ of the same number,then what will be $80 \%$ of the number?

Find a single equivalent increase,if a number is successively increased by $10 \%$,$20 \%$,and $25 \%$. (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?

$A$ set $A$ consists of integers $27, 28, 30, 32$ and $33$. If an integer $K$ is included,the average of set $A$ will increase by $30\%$. What is the value of integer $K$?