The true discount (TD) on a certain sum due 6 months hence at 15% p.a. is ₹240. What is the banker’s discount (BD) on the same sum for the same time and rate?
Aptitude
Banker's Discount
Difficulty: Easy
Choose an option
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ARs. 248
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BRs. 278
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CRs. 228
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DRs. 258
Answer
Correct Answer: Rs. 258
Explanation
Introduction / Context:Given TD and (rate × time), BD is just a simple multiplier away. The ratio BD/TD equals 1 + x where x = r * t. We leverage this direct relation for a quick computation.
Given Data / Assumptions:
- TD = ₹240.
- t = 6 months = 0.5 year; r = 15% p.a. ⇒ x = 0.075.
Concept / Approach:Identity: BD = (1 + x) * TD. No need to find the face value explicitly. Compute x, multiply TD by (1 + x).
Step-by-Step Solution:
x = 0.15 * 0.5 = 0.075.BD = (1 + x) * TD = 1.075 * 240 = ₹258.Verification / Alternative check:If TD = 240 and x = 0.075, then BD − TD = x * TD = 18 ⇒ BD = 258, consistent.
Why Other Options Are Wrong:₹228, ₹248, and ₹278 do not equal 1.075 * 240.
Common Pitfalls:Forgetting to convert months to years before computing x; mixing up BD and BG.
Final Answer:Rs. 258