Difficulty: Medium
Correct Answer: Cannot be determined with the given data
Explanation:
Introduction / Context:
This question tests your understanding of the relationship between principal, rate, time, and interest in simple interest problems. It also focuses on whether the given data are sufficient to compute a unique numerical answer. Many aptitude questions are designed to see if you correctly identify that there are too many unknowns compared to the number of equations provided.
Given Data / Assumptions:
Concept / Approach:
From the given information, we can form one equation involving P and r using the simple interest formula. However, there are two unknowns and only one equation, so P and r individually cannot be obtained. To find the extra interest when the rate increases by 1%, we need the value of P. Since P depends on both r and the known interest, and r is unknown, there will be infinitely many possible values for P that satisfy the equation. Therefore the additional interest cannot be uniquely fixed.
Step-by-Step Solution:
Step 1: Use SI = (P * r * T) / 100 with SI = 2260 and T = 3.
Step 2: 2260 = (P * r * 3) / 100.
Step 3: Rearranging gives P * r = (2260 * 100) / 3.
Step 4: Thus, P * r is known numerically, but P alone and r alone are not known.
Step 5: If the rate were (r + 1)%, the new simple interest in 3 years would be SI_new = (P * (r + 1) * 3) / 100.
Step 6: The additional interest would be SI_new - SI_original = (P * 3 / 100) * (r + 1 - r) = (3P) / 100.
Step 7: To compute (3P) / 100 exactly, we need P. However, we only know P * r, not P.
Step 8: Different combinations of P and r can give the same product P * r, so multiple answers for the extra interest are possible.
Verification / Alternative check:
Assume some trial value of r that satisfies the original equation and compute P from P = (2260 * 100) / (3 * r). For a different value of r that also satisfies the equation, a different P will result, giving a different value of (3P) / 100. This shows there is no single unique amount for the additional interest, confirming that the data are insufficient.
Why Other Options Are Wrong:
Any numerical option such as Rs 175, Rs 220.75, Rs 126, or Rs 150 assumes a specific fixed principal, which is not determined by the information given. Since P is not uniquely determined, none of these fixed values can be guaranteed to be correct in every consistent scenario. Hence, all numerical options are unjustified.
Common Pitfalls:
A common mistake is to try to assume a convenient rate and principal without realizing that many different combinations satisfy the original simple interest equation. Another error is to treat P * r as if it directly gives P or r. Always check the number of independent equations versus the number of unknowns before concluding you have a unique answer.
Final Answer:
The additional interest cannot be uniquely determined, so the correct choice is Cannot be determined with the given data.
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