Circular track 14 m wide; inner circumference 440 m: Find the radius of the outer circle.
Aptitude
Area
Difficulty: Easy
Choose an option
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A84 m
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B24 m
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C44 m
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D54 m
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ENone of these
Answer
Correct Answer: 84 m
Explanation
Introduction / Context:A track has uniform width. Knowing the inner circumference gives the inner radius; the outer radius is inner radius plus width.
Given Data / Assumptions:
- Width w = 14 m.
- Inner circumference = 440 m ⇒ 2πr_in = 440.
Concept / Approach:r_in = 440 / (2π). Then r_out = r_in + 14.
Step-by-Step Solution:
1) Using π ≈ 22/7: r_in = 440 / (2 * 22/7) = 440 * 7 / 44 = 70 m.2) r_out = 70 + 14 = 84 m.Verification / Alternative check:Outer circumference would then be 2π*84 ≈ 528π/ ? Not needed; radius result is direct.
Why Other Options Are Wrong:24, 44, 54 do not equal 70 + 14.
Common Pitfalls:Subtracting the width instead of adding for the outer radius.
Final Answer:84 m.