Difficulty: Medium
Correct Answer: 232
Explanation:
Introduction:
This is a percentage and approximation problem commonly seen in bank and aptitude exams. You are asked to evaluate an expression involving percentages of large numbers and then add a constant. The focus is on calculating accurately and then rounding sensibly to the nearest integer. Understanding how to convert percentages into simple multiplication is the key idea here.
Given Data / Assumptions:
Concept / Approach:
Convert each percentage to its decimal or fractional form and multiply by the number. Then subtract the two percentage values, and finally add 63. Since these are straightforward arithmetic operations, it is best to perform them step by step, and round only at the end to avoid compounding rounding errors.
Step-by-Step Solution:
47% of 1442 = (47/100) * 1442 = 677.74.36% of 1412 = (36/100) * 1412 = 508.32.Difference = 677.74 - 508.32 = 169.42.Now add 63: 169.42 + 63 = 232.42.Rounded to the nearest integer, 232.42 ≈ 232.
Verification / Alternative check:
You can approximate the calculations more roughly and still see that the final value is close to 232. For example, 47% of 1440 ≈ 0.47 * 1440 ≈ 677, and 36% of 1410 ≈ 0.36 * 1410 ≈ 508. The difference is around 169 and adding 63 gives roughly 232. This matches our precise calculation.
Why Other Options Are Wrong:
228 and 230: These are somewhat close but off by more than 2 units from the computed value 232.42.235 and 240: These are clearly larger than the accurate result and correspond to overestimation of the intermediate percentage calculations.
Common Pitfalls:
Rounding the percentage values too early, which can distort the final sum.Confusing percentage subtraction (47 - 36 = 11) and applying 11% directly without separating the numbers 1442 and 1412, which are different.Forgetting to add the constant 63 at the end.
Final Answer:
232
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