Difficulty: Easy
Correct Answer: 652
Explanation:
Introduction / Context:
This aptitude question translates a sentence about fractions into a simple linear equation. The expression “three-fourths of a number subtracted from the number” is a common prompt to test algebraic modeling and careful reading. Solving it requires only basic manipulation once the equation is set up correctly.
Given Data / Assumptions:
Concept / Approach:
The wording maps directly to the equation: N − (3/4)N = 163. Combine like terms on the left to isolate a single multiple of N, then solve by division. The structure highlights how fractional parts of a whole relate back to the whole number.
Step-by-Step Solution:
Write the relation: N − (3/4)N = 163.Combine: (1 − 3/4)N = (1/4)N = 163.Solve for N: N = 163 * 4 = 652.Therefore, the original number is 652.
Verification / Alternative check:
Compute 3/4 of 652 = 489. Then N − 3/4 N = 652 − 489 = 163, matching the given condition exactly.
Why Other Options Are Wrong:
625, 562, 632, and 640 produce N − 3/4 N values of 156.25, 140.5, 158, and 160 respectively, none equal to 163.
Common Pitfalls:
Misreading “three-fourths” as “three-four” or interpreting the phrase as (3/4N − N). Also, some candidates multiply 163 by 3 inadvertently instead of by 4.
Final Answer:
652
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