Difficulty: Medium
Correct Answer: 1/10
Explanation:
Introduction / Context:This problem requires careful tracking of money transfers in two stages. It tests proportional reasoning and equation setup: first, compute each person’s holdings after the first transfer; then, determine the fraction of B’s new amount that must be transferred back to A for equality after the second game.
Given Data / Assumptions:
Concept / Approach:Let the transfer in Game 2 be f*(5k/3) from B to A. Set the final amounts equal and solve for f. The ratio relationship 4k/3 vs 5k/3 makes the algebra neat and the result a simple fraction.
Step-by-Step Solution:
After Game 1: A1 = 4k/3, B1 = 5k/3.Game 2 transfer: T = f * B1 = f * (5k/3).Final amounts: A2 = A1 + T; B2 = B1 − T.Set equality: A1 + T = B1 − T ⇒ A1 = B1 − 2T.Substitute: 4k/3 = 5k/3 − 2f*(5k/3) ⇒ 4/3 = 5/3 − (10/3)f.Solve: (10/3)f = 5/3 − 4/3 = 1/3 ⇒ f = (1/3) * (3/10) = 1/10.Verification / Alternative check:
With f = 1/10, T = (1/10)*(5k/3) = k/6. A2 = 4k/3 + k/6 = 9k/6 = 3k/2; B2 = 5k/3 − k/6 = 9k/6 = 3k/2: equal.Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
1/10
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