In a motor of $120$ machine parts,$5 \%$ parts were defective. In another motor of $80$ machine parts,$10 \%$ parts were defective. For the two motors considered together,the percentage of defective machine parts was (in $\%$)

If a number is $20 \%$ more than the other,how much per cent is the second number less than the first?

$860\%$ of $50 + 50\%$ of $860 = ?$

$A$ 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?

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

$39.897 \%$ of $4331 + 58.779 \%$ of $5003 = ?$