Difficulty: Medium
Correct Answer: 1%
Explanation:
Introduction / Context:
True discount TD for a future sum S due after t years at rate r (per annum) under simple interest is TD = S * r * t / (1 + r * t). Knowing TD, S, and t allows solving for r. This is a standard algebraic inversion.
Given Data / Assumptions:
Concept / Approach:
Let u = r * t. Then TD = S * u / (1 + u). Solve u from 2,000 = 50,000 * u / (1 + u), then compute r = u / t.
Step-by-Step Solution:
Verification / Alternative check:
Using r ≈ 1.0417% gives TD ≈ 50,000 * (0.010417*4) / (1 + 0.010417*4) ≈ 2,000; rounding to the nearest listed rate is appropriate.
Why Other Options Are Wrong:
1.5%, 2%, and 5% produce TD far from ₹ 2,000 for 4 years; 0.75% underestimates.
Common Pitfalls:
Omitting the denominator (1 + r t) and equating TD to S r t, which would overstate the rate.
Final Answer:
1%
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