Similar question came in gate this year also..
So here the key point u have to remember is :
When head changes direction , then the entire head movement from last to first head position or vice versa will be covered and hence considered in head movements..However the transition is momentary so seek time will not be involved in this transition from one extreme to another extreme.
So considering the above fact , we have :
No of head movements(seek distance) = (67 - 45) + (87 - 67) + (240 - 87) + (255 - 240) + 255 + (11 - 0) + (40 - 11)
= 22 + 20 + 153 + 15 + 255 + 11 + 29
= 505
Hence seek distance = 505
