Solution: If the distance of line B is x meters, the distance of line A is X × (1+20%) meters.

Because Party A and Party B walk in opposite directions, Party A walks 20% more than Party B and meets at a distance of 60 meters from the midpoint.

So the distance of line A is half the distance plus 60 meters.

So we can list the equation: x+x× (1+20%) = [x× (1+20%)-60 ]× 2.

The distance of A plus the distance of B (equivalent to the whole journey of AB) = the distance of A minus 60m (equivalent to half the distance) ×2.

X = 600 meters

The distance traveled by Line A is: 600× (1+20%) = 720m.

So the distance between A and B is: 600+720 =1320m.

Midpoint: 1320 ÷ 2 = 660 (m)