Difficulty: Medium
Correct Answer: ₹264
Explanation:
Introduction / Context:
This classic TD–SI linkage uses the time-rate factor R = r * t (in decimal). For the same “sum due” S and same time, the simple interest on S is S * R, while the true discount is S * R / (1 + R). Their ratio eliminates S and gives R directly; then recover S from the given SI value.
Given Data / Assumptions:
Concept / Approach:
For the same S and R: SI = S * R and TD = S * R / (1 + R). Hence TD/SI = 1/(1 + R). Use the numerical values to find R. Then S = SI / R.
Step-by-Step Solution:
Verification / Alternative check:
TD predicted = S * R / (1 + R) = 264 * (1/11) / (12/11) = 24 / 12 = ₹22, matching the given TD.
Why Other Options Are Wrong:
₹220, ₹288, ₹295, ₹242 do not satisfy both SI = 24 and TD = 22 under a single R.
Common Pitfalls:
Assuming SI equals TD (that holds when SI is on present worth, not on the sum due S). Here SI is on S.
Final Answer:
₹264
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