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GATE 2021 IN – Question 7

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

Two rectangular sheets M and N each measure 6 cm × 4 cm. Folding operation 1 halves the sheet by joining the short edges of its current shape. Operation 2 halves it by joining the long edges of its current shape. Apply operation 1 to M three times and operation 2 to N three times. The ratio of final perimeters N:M is ______.

  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

For M, joining the current short edges halves the longer dimension: 6×4→3×4→3×2→1.5×2, perimeter 7 cm. For N, joining the long edges repeatedly halves the shorter dimension: 6×4→6×2→6×1→6×0.5, perimeter 13 cm.

Therefore PN/PM=**13:7, A**. Reidentify long and short edges after every fold.