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GATE 2025 ES – Question 62

Solid and Hazardous Waste Management · Municipal Solid Waste Management · 2 marks · Numerical answer

A street sweeper starts at P, ends at S, and must traverse every street at least once. Edge lengths in km are shown. Find the minimum total distance in integer km.

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Correct answer: 16 to 16

Explanation

Total edge length is $PQ+PR+QR+QS+RS=2+3+4+3+1=13$ km. Initially Q and R are odd-degree vertices; a route beginning P and ending S needs P and S odd instead. Minimum duplicated paths pair P with Q (2 km) and R with S (1 km),adding3. The competing pairing P–R and Q–S adds6; pairing P–S and Q–R adds8. A 16 km route exists, for example P–Q–P–R–Q–S–R–S. Thus **16 km**.

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