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Venu

· started a discussion

· 1 Months ago

correct it

Question:
By melting a solid lead sphere of diameter 12 cm, three small spheres are made whose radii are in the ratio 3 : 4 : 5. The radius (in cm) of the smallest sphere is-
Options:
A) 3
B) 6
C) 1.5
D) 4
Solution:

Ans: (a)

nikhil

· commented

· 1 Months ago

Yes answer shout be 1.5

suresh kommara

· commented

· 1 Months ago

below comment * not cylinder its sphere.. typos

suresh kommara

· commented

· 1 Months ago

answer is correct..

volume of cylinder = 4/3 * pi * r^3

4/3 * pi *6*6*6 = 4/3 * pi * { [3k/2 ]^3 + [4k/2]^3 + [5k/2]^3 }

6*6*6* 2^3 = [ 3^3 + 4^3 + 5^3 ] * k^3

6*6*6* 2^3 = 216 * k^3

2^3 = k^3

hence k=2

The radius (in cm) of the smallest sphere is = 3k/2 = 3*2/2 = 3

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