# A cylindrical rod of radius 30 cm and length 40 cm is melted and made into spherical balls

A cylindrical rod of radius 30 cm and length 40 cm is melted and made into spherical balls of radius 1 cm. The number of spherical balls is

(a) 36000

(b) 27000

(c) 90000

(d) 40000

**Answer: (b) 27000 **

**Solution:-**

The radius of a cylindrical rod = 30 cm

And, height of the cylindrical rod = length of cylindrical rod = 40 cm

Then, the volume of the cylindrical rod = pai x (30)^2 x 40

= 36000 pai cm^2

The radius of spherical ball = 1 cm

Then, the volume of spherical ball = 4 pai x (1)^3/3

= 4 pai/3

So, the number of spherical balls = 36000 pai x 3/4 x pai

= 9000 x 3

= 27, 000

Then, the number of spherical balls is 27000.

Hence, the correct answer is option (b) 27000.