$23 \%$ of $8040 + 42 \%$ of $545 = ? \%$ of $3000$

Two jars contain equal quantities of $40 \%$ alcohol. Swati changed the concentration of the first jar to $50 \%$ by adding extra quantity of pure alcohol. Sonali changed the concentration of the second jar to $50 \%$ by replacing a certain quantity of the solution with pure alcohol. By what percentage is the quantity of alcohol added by Swati more than that replaced by Sonali?

The population of a town increases by $5 \%$ annually. If its population in $2001$ was $138915$,what was it in $1998$?

What fraction is $0.6 \%$?

In a test,a candidate secured $468$ marks out of maximum marks $A$. Had the maximum marks $A$ been converted to $700$,he would have secured $336$ marks. What was the maximum marks $A$ of the test?

The first and second numbers are less than a third number by $30 \%$ and $37 \%$,respectively. The second number is less than the first by: (in $\%$)