A man walks diagonally across a square plot instead of along two edges. Approximately what percentage distance is saved by taking the diagonal path?
Aptitude
Area
Difficulty: Easy
Choose an option
-
A10%
-
B20%
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C30%
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D40%
Answer
Correct Answer: 30%
Explanation
Introduction / Context:Distance saved equals (edge path − diagonal) / edge path. In a square of side s, the edge path from one corner to the opposite via two sides is 2s, while the straight diagonal distance is s√2.
Given Data / Assumptions:
- Square side = s (symbolic; cancels out).
Concept / Approach:Compute percent saving = [(2s − s√2) / (2s)] * 100% = [1 − (√2)/2]*100%.
Step-by-Step Solution:
Saving fraction = 1 − √2/2 ≈ 1 − 0.7071 ≈ 0.2929Saving percent ≈ 29.29% ≈ 30%Verification / Alternative check:Set s = 1. Edge path = 2, diagonal ≈ 1.4142, saving ≈ 0.5858 ≈ 29.3% of 2.
Why Other Options Are Wrong:
- 10%, 20%: Underestimates.
- 40%: Overestimates.
Final Answer:30%