Head movement of LOOK algorithm is :$(105-100)+(110-105)+(126-110)+(135-126)+(195-135)+(195-85)+(85-55)+(55-30)$
Total distance for LOOK algorithm: $260$
Head movement of CSCAN algorithm:$(105-100)+(110-105)+(126-110)+(135-126)+(195-135)+(199-195)+(199-0)+(30-0)+(55-30)+(85-55)$
Total distance for CSCAN= $383$
So the difference is : $383-260=123$