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GATE 2021 CE (CE1) – Question 7

General Aptitude · Spatial Aptitude: Spatial Reasoning and Visualization · 2 marks · Multiple choice

Sheets M and N each measure 6 cm × 4 cm. Operation 1 folds a sheet in half by joining its current short edges; operation 2 joins its current long edges. M undergoes operation 1 three times and N operation 2 three times. Find final perimeter ratio N:M.

  1. 13:7
  2. 3:2
  3. 7:5
  4. 5:13

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Show answer and explanation

Correct answer: (A) 13:7

Explanation

Joining the short edges halves the current longer dimension: M changes 6×4→3×4→3×2→1.5×2, with perimeter 7 cm. Joining long edges halves the shorter dimension: N changes 6×4→6×2→6×1→6×0.5, with perimeter 13 cm. Hence **N:M=13:7 (A)**.