The cost of painting a solid cone at 30 paise per cm² is ₹660. Find the radius of the cone if its slant height is 15 cm. (Use π = \( \frac{22}{7} \))
Find the value of 60 ÷ 5 ×\(\left(\frac{9}{8} \ of \frac{4}{3} \div \frac{3}{4} \ of \frac{2}{3}\right)\).
If 9 persons can do a job in 18 days, then 18 persons with twice the efficiency can do the same job in:
\( \frac{9}{2} \) days
\( \frac{5}{2} \)days
\( \frac{11}{2} \) days
\( \frac{7}{2} \) days
A sphere of radius 6 m is cut into two equal halves. Find the volume of each hemisphere so formed. (Use π = \( \frac{22}{7} \))