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

Anurag Mishra Professor Asked on 26th March 2016 in Maths.
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1 Answer(s)

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.

Anurag Mishra Professor Answered on 27th March 2016.
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