A right circular cylinder having diameter 12 cm and height 15 cm is full ice-cream. The ice-cream is to be filled in cones of height 12 cm and diameter 6 cm having a hemispherical shape on the top. Find the number of such cones which can be filled with ice-cream.
Given radius of cylinder (r’) = 
= 6 cm
Given radius of hemisphere (r’’) = 
=3 cm
Given height of cylinder (h) = 15 cm
Height of cone (l) = 12 cm
Volume of cylinder = πr2h
= πr(6)2(15) cm ………. (1)
Volume of each cone = Volume of cone + Volume of hemisphere
V = π(r)2(l) + 
π(r)3
V = π(3)2(12) + 
π(3)3 ………… (2)
Let number of cone be n
n (volume of each cone) = volume of cylinder
n = [(
π(3)2 (12) + 
π(3)3] = π(16)2 15
⇒ n = 10
20