Atul invests a sum of ₹5,400 and Nirmal invests a sum of ₹10,200 at the same rate of simple interest per annum. If, at the end of 5 years, Nirmal gets ₹480 more interest than Atul, then find the rate of interest per annum (in percentage).
A cylindrical tank has a capacity of 4774 m³. If the radius of the base is 7 m, what is the depth? (Use π = \( \frac{22}{7} \))
400 apples were bought at ₹1,220 per hundred and were sold at a profit of ₹920. Find the selling price (in ₹) per dozen of apples.