The banker’s gain (BG) on a certain sum due 2 years hence at 10% p.a. is ₹24. What is the present worth (PW)?
Aptitude
Banker's Discount
Difficulty: Easy
Choose an option
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ARs. 600
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BRs. 500
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CRs. 400
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DRs. 300
Answer
Correct Answer: Rs. 600
Explanation
Introduction / Context:With BG and x known, PW follows from BG = x^2 * PW. This method is efficient because it does not require determining face value first or computing TD separately unless desired for checking.
Given Data / Assumptions:
- r = 10% p.a., t = 2 years ⇒ x = 0.20.
- BG = ₹24.
Concept / Approach:Use BG = x^2 * PW. Thus PW = BG / x^2. Straight substitution yields the answer immediately.
Step-by-Step Solution:
x = 0.1 * 2 = 0.2; x^2 = 0.04.PW = 24 / 0.04 = ₹600.Verification / Alternative check:TD = x * PW = 0.2 * 600 = ₹120; BG = x * TD = 0.2 * 120 = ₹24, correct.
Why Other Options Are Wrong:₹300, ₹400, ₹500 produce BG values different from ₹24 when multiplied by x^2 = 0.04.
Common Pitfalls:Using BD or other intermediate steps unnecessarily; the direct identity suffices.
Final Answer:Rs. 600