$x\%$ of $932 + 30 = 309.6$. Find the value of $x$.

The price of a house increases every year by $20 \%$. If the present price is $Rs \ 720000$,then what was its price (in $Rs$) $2$ years ago?

In an election between two candidates,one got $55 \%$ of the total valid votes,and $20 \%$ of the total votes were invalid. If the total number of votes was $7500$,what was the number of valid votes that the other candidate received?

The percentage increase in the surface area of a cube when each side is doubled is:

If the length and breadth of a rectangular field are increased,the area increases by $50 \%$. If the length is increased by $20 \%$,by what percentage was the breadth increased?

The average marks obtained in a class of $50$ students is $70 \%$. The average of the first $25$ students is $60 \%$ and that of the next $24$ students is $80 \%$. What is the percentage of marks obtained by the last student?