The mean proportional of x and y is z. What is the mean proportional of x²z and y²z?
Find the value of [(21 ÷ 7) × {(\( \frac{63}{9} \)) + (\( \frac{14}{2} \)) × (4 − 2)}]
400 pears were bought at ₹1,200 per hundred and sold at a profit of ₹1,000. Find the selling price per dozen of pears (in ₹).