If 6 × (A’s capital) = 8 × (B’s capital) = 10 × (C’s capital), what is the ratio A : B : C of their capitals?
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A3 : 4 : 5
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B12 : 15 : 20
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C20 : 15 : 12
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D6 : 8 : 10
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E5 : 4 : 3
Answer
Correct Answer: 20 : 15 : 12
Explanation
Introduction / Context:When equal products are given, set each equal to a common constant and solve for the variables. This is a standard technique to extract ratios from equations like 6A = 8B = 10C.
Given Data / Assumptions:
- 6A = 8B = 10C = k (common constant).
Concept / Approach:Express A, B, C in terms of k and compare. Because A = k/6, B = k/8, C = k/10, the ratio is the triplet of reciprocals 1/6 : 1/8 : 1/10. Clear denominators to reach integers.
Step-by-Step Solution:A = k/6, B = k/8, C = k/10A : B : C = (1/6) : (1/8) : (1/10)Multiply by LCM(6,8,10) = 120 ⇒ 20 : 15 : 12
Verification / Alternative check:Check: 6*20 = 120; 8*15 = 120; 10*12 = 120; all equal.
Why Other Options Are Wrong:3 : 4 : 5 matches 6A = 8B = 10C only if scaled incorrectly; 6 : 8 : 10 is the product multipliers, not the capitals.
Common Pitfalls:Confusing the coefficients (6, 8, 10) with the final ratio; remember the variables are inversely proportional to those coefficients.
Final Answer:20 : 15 : 12