In an examination,there are three papers and a candidate has to get $35 \%$ of the total to pass. In one paper,he gets $62$ out of $150$ and in the second $35$ out of $150$. How much must he get,out of $180$,in the third paper to just qualify for a pass?

In expressing a length $81.472 \, km$ as nearly as possible with three significant digits,find the percentage error?

The percentage of metals in a mine of lead ore is $60 \%$. Now, the percentage of silver is $3/4 \%$ of the metals and the rest is lead. If the mass of ore extracted from this mine is $8000 \, kg$, what is the mass (in $kg$) of lead?

$\frac{3}{4}$ of $\frac{2}{3}$ of $\frac{1}{5}$ of a number is $249.6$. What is $50\%$ of that number?

When the price of sugar decreases by $10 \%$,a man can buy $1 \text{ kg}$ more for $₹ 270$. What is the original price of sugar per $\text{kg}$?

$A$ businessman imported laptops worth $Rs$ $210,000$,mobile phones worth $Rs$ $100,000$,and television sets worth $Rs$ $150,000$. He had to pay $10\%$ duty on laptops,$8\%$ on phones,and $5\%$ on television sets. How much total duty (in Rupees) did he have to pay on all items as per the above details?