Cones — Volumes in ratio 1:4; diameters in ratio 4:5. Find the ratio of their heights.
Aptitude
Volume and Surface Area
Difficulty: Medium
Choose an option
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A1 : 5
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B5 : 4
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C5 : 16
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D25 : 64
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E4 : 5
Answer
Correct Answer: 25 : 64
Explanation
Introduction / Context:For cones, V ∝ r^2 h. With diameter ratio 4:5, radius ratio is 2:2.5 = 4:5. Use the volume ratio to solve for height ratio.
Given Data / Assumptions:
- V1:V2 = 1:4
- r1:r2 = 4:5 ⇒ r1^2:r2^2 = 16:25
Concept / Approach:(r1^2 h1):(r2^2 h2) = 1:4 ⇒ (16 h1):(25 h2) = 1:4 ⇒ h1/h2 = (1/4) * (25/16) = 25/64.
Step-by-Step Solution:h1:h2 = 25:64
Verification / Alternative check:Check by plugging into V ∝ r^2h.
Why Other Options Are Wrong:They ignore r^2 or invert ratios.
Common Pitfalls:Using diameter directly without squaring radius in volume.
Final Answer:25 : 64