Three solid spheres of radius 3 cm, 4 cm and 5 cm are melted and recasted into a solid sphere. What will be the percentage decrease in the surface area?
The average revenues of 9 consecutive years of a company is Rs 65 lakhs. If the average of first 5 years is Rs 60 lakhs and that of last 5 years is Rs 72 lakhs, find the revenue for the 5th year.