Question

A computer has six tape drives, with n processes competing for them. Each process may need two drives. What is the maximum value of n for the system to be deadlock free?

Answer 1

Every process needs 2 resources. With 5 resources atleast one can get whole 2 and executes. So after execution it frees 2 resources which can be used by other processes.
$P_1$ $P_2$ $P_3$ $P_4$ $P_5$
1 1 1 1 1