Consider the following relation with $150,000$ tuples, stored in $3,000$ pages:

STUDENTS$($SID$,$ Name, DeptID, Email, GPA$)$

Each of the five attributes requires the same amount of storage space. An alternative$-2$

unclustered tree index with fanout $F$ is created for the search key DeptID.

a$)$ What is the number of disk I$/$Os required to retrieve the $300$ students in

Department $4710?$

b$)$ What is the $\frac{1}{0}$ cost if a clustered hash index is used?