Consider two rectangular sheets, Sheet M and Sheet N of dimensions $6 \mathrm{cm} \times 4 \mathrm{cm}$ each. Folding operation 1: The sheet is folded into half by joining the short edges of the current shape. Folding operation 2: The sheet is folded into half by joining the long edge of the current shape. Folding operation 1 is carried out on sheet M three times. Folding operation 2 is carried out on sheet N three times. The ratio of perimeters of the final folded shape of sheet N to the final folded shape of sheet M is ____ .
(a)3 : 2
(b)5 : 13
(c)$7: 5$
(d)$13: 7$
Answer
Answer: D ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
Sheet M (joining short edges halves the long side each time): 6×4 → 3×4 → 3×2 → 1.5×2, perimeter 7. Sheet N (joining long edges halves the short side): 6×4 → 6×2 → 6×1 → 6×0.5, perimeter 13. N : M = 13 : 7.