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555-605 (Medium)|   Geometry|      
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MathRevolution
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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surf 19 Jan 2017, 01:34
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D
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75% (01:17) correct 25% (01:31) wrong based on 126 sessions

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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surface area is how many times of sphere B’s surface area?

A. 4 B. 8 C. 12 D. 16 E. 32
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D
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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surf 19 Jan 2017, 21:31
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D.

Va/Vb = 64/1 = (Ra/Rb)^3 => (Ra/Rb) =4

Sa/Sb = (Ra/Rb)^2 = 4^2 = 16
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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surf 22 Jan 2017, 22:32
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==> Since sphere A’s volume is 64 times of sphere B’s volume, sphere A’s length is Sphere A’s \(3√64\)times of sphere B’s length, in other words,\(3√4^3=4\). However, since the ratio of the surface area is equal to the square of ratio of the length, you get 4^2=16, hence 16 times.

Therefore, the answer is D.
Answer: D
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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surf 20 Mar 2017, 14:55
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MathRevolution
==> Since sphere A’s volume is 64 times of sphere B’s volume, sphere A’s length is Sphere A’s \(3√64\)times of sphere B’s length, in other words,\(3√4^3=4\). However, since the ratio of the surface area is equal to the square of ratio of the length, you get 4^2=16, hence 16 times.

Therefore, the answer is D.
Answer: D
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Could you explain this logic further, please? Am I missing a special formula or something?
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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surf 21 Mar 2017, 03:28
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Va/Vb = 64/1 = (Ra/Rb)^3 => (Ra/Rb) =4

Sa/Sb = (Ra/Rb)^2 = 4^2 = 16

option D
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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surf 21 Mar 2017, 11:42
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ByjusGMATapp
Va/Vb = 64/1 = (Ra/Rb)^3 => (Ra/Rb) =4

Sa/Sb = (Ra/Rb)^2 = 4^2 = 16

option D
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You just copied what someone else already wrote...can you explain it with words and not just another equation? What is the logic?
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If sphere A’s volume is 64 times of sphere B’s volume, sphere A’s surf 05 May 2021, 13:43
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