If you use a rope to wrap around the column for 2 turns, the rope will be 40 cm more. If you wrap around the column for 3 turns, the rope will be 20 cm less. How long is the rope? How to list the formula

If you use a rope to wrap around the column for 2 turns, the rope will be 40 cm more. If you wrap around the column for 3 turns, the rope will be 20 cm less. How long is the rope? How to list the formula

Let the length of the rope be x cm and the perimeter of the column be y cm
2y+40=x ,3y-x=20
x=160