Difficulty: Medium
Correct Answer: ₹139.20
Explanation:
Introduction / Context:
When a uniform path runs inside a rectangle, the path area equals outer area minus inner rectangle area. Here, obvious unit typos are interpreted reasonably (metres throughout, 0.5 m path).
Given Data / Assumptions:
Concept / Approach:
Inner rectangle dimensions reduce by 2w in each direction. Path area = Outer − Inner.
Step-by-Step Solution:
Verification / Alternative check:
Approximate path area also equals perimeter * width − 4 * (w^2) for thin paths: 2(110+65)*0.5 − 4*(0.25) = 350*0.5 − 1 = 175 − 1 = 174 m^2, same result.
Why Other Options Are Wrong:
₹340, ₹320, and ₹480 arise from misread unit rates or dimensions; only ₹139.20 matches the corrected interpretation and exact calculation.
Common Pitfalls:
Using centimetres inadvertently or treating the cost as ₹80 per m^2 instead of ₹0.80 per m^2 drastically overstates the amount.
Final Answer:
₹139.20
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