AB is set to A and CB is set to B. Because the time is the same, the distance and speed ratio of cats and mice are the same, which can be set to 14x and 1 1x, that is to say, the perimeter can be14x+1kloc-0/x = 25x.

Cat distance: 14x=a+b+6.

Mouse distance: 1 1x=a+(b-6)

You can cancel a+b, 3x= 12 and get x=4.

Then the circumference is 25x=25*4= 100m.