Mathematics: the logging depth of a rope is reduced by 2, the remaining amount outside the well is 10 meter, and the amount outside the well is reduced by 3 to 4 meters. How many meters is the rope and how many meters is the well? Solution: When the rope is folded twice, the rope length is twice the well depth plus 10× 2m, and when the rope is folded three times, the rope length is four times the well depth plus 4× 3m.

∴ Well depth: 10× 2-4× 3 = 8m.

Rope length: (8+ 10) × 2 = 36m.

Answer: The rope is 36 meters long and the well is 8 meters deep.