If $200 \%$ of a number is $90,$ then what is the $80 \%$ of that number?

In the month of January,the Railway Police caught $4,000$ ticketless travellers. In February,the number rose by $5\%$. However,due to constant vigil by the Police and the Railway staff,the number reduced by $5\%$ in March and in April it further reduced by $10\%$. The total number of ticketless travellers caught in the month of April was:

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

The price of a shirt is increased by $15 \%$ and then reduced by $15 \%$. The final price of the shirt

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?

$a \%$ of $b + b \%$ of $a =$