Question

A blacksmith have big iron ball of diameter
36cm. He first formed four identical
cylindrical rod out of this ball for some
construction work. When he finished his
work with the cylindrical rod, he again
mixed all the iron rod and formed some
identical small balls, each of radius 9cm.

(i)
When one solid is converted to
another solid shape, their-
(i) Surface area remain same
(ii) Volume remain same
Which of the above options is/are true:
(a) Only (i)
(b) Only (ii)
(c) Both (i) and (ii)
(d) None of them.

(ii)
If the diameter of each cylinder
formed by him is 12cm, then height
of each of them is-
(a) 54cm
(b) 36cm
(c) 45cm
(d) 72cm
(iii)
The number of small balls formed by the
blacksmith?
(a) 6
(b) 10
(c) 8
(d) 16

(iv)
What is the cost price of steel coating of a
cylindrical iron rod at the rate of Rs.3.5per
100cm2
?
(a) Rs.79.20
(b) Rs.89.20
(c) Rs.85.56
(d) Rs.71.28

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Answer 1

I don't know , please forgive me dear friend...