Made easy question: Disk scheduling

Question

Answer 1

Since First Come First Served policy is used, total seeks is given by: $(20-10)+(22-10)+(22-20)+(20-2)+(40-2)+(40-6)+(x-6)$

As time for one seek is 6 ms, total time taken is: $[(20-10)+(22-10)+(22-20)+(20-2)+(40-2)+(40-6)+(x-6)]*6$

Given that total seek time is 876 ms. So, we can write:

$[(20-10)+(22-10)+(22-20)+(20-2)+(40-2)+(40-6)+(x-6)]*6=876 \implies 108+x =146 \implies x=38$

Comments

Yes I got it! Actually I missed that 22 - 20 part. Now I got it! Thank you so much

---

@Jaspreet Singh

Our head starts from $20$, why we serviced again?

Answer 2

Difference is 10+12+2+18+38+34=114

And .Take options a =32*6=192

Difference is 114*6=684

684+192=876

Options A is correct