Q62

A disk has $200$ tracks (numbered $0$ through $199$). At a given time, it was servicing the request of reading data from track $120$, and at the previous request, service was for track $90$. The pending requests (in order of their arrival) are for track numbers. $30 \ 70 \ 115 \ 130 \ 110 \ 80 \ 20 \ 25.$ How many times will the head change its direction for the disk scheduling policies SSTF(Shortest Seek Time First) and FCFS (First Come First Serve)?