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?

If the side of a square is increased by $30 \%,$ its area is increased by:

$16 \frac{2}{3} \%$ of $600 \, \text{gm} - 33 \frac{1}{3} \%$ of $180 \, \text{gm}$

Sashi has $Rs. 90000$ with him. He purchases a mobile,an iPad,and a laptop for $Rs. 15000$,$Rs. 13000$,and $Rs. 35000$ respectively and puts the remaining money in his bank account which pays $15 \%$ per annum compound interest. After $2$ years,he sells off the three items at $80 \%$ of their original price and also withdraws his entire money from the bank by closing the account. What is the total percentage change in his assets (in $\%$)?

Which number is $60 \%$ less than $80$?

In a recent opinion poll held during April,$60 \%$ of the respondents favoured India Against Corruption $(IAC)$ while the rest favoured Indian political parties $(IPP).$ It was found in May polls that $10 \%$ of $IAC$ supporters switched their preference to $IPP,$ while the same percentage of $IPP$'s supporters also switched their preference to $IAC.$ What percentage of the electorate should now switch their preference from $IAC$ to $IPP$ so that they are at par?