Self-doubt

Question

Process	maximum demand	currently holds
P1	70	45
P2	60	40
P3	60	X
P4	40	Y

If a system has total of 150 units of resource , identify which of the following values of X and Y the above system will be in safe state?

1. X = 40 , Y = 20

2. X = 50 , Y = 10

3. X = 30 , Y = 20

4. X = 20 , Y = 30

Answer 1

D is the answer ..

WE have total of 150 resources ..out of which 40 and 45 means total of 85 are allocated to space P1 and P2 .

Now remaining resources are 150-85=65.

Now say we allocate 20 resources to P3 so required for P3 are 40 

we will allocate 30 resoures to P4 so we need 10 for its execution ....

so table will be 

Process	Max	Allocated	Needed
P1	70	45	25
P2	60	40	20
P3	60	20	40
P4	40	30	10

Still remaining resources are 150-(45+40+20+30)=150-(85+50)=15 

So with 15 resourecs in hand we can give it to P4 ..

Once P4 done we have 40 Resources in hand we can easily satisfy the need of other Process So 

D is the Correct Option.

Comments

Cool..thanks for clearing the doubt...now I understand why c can't be right. I was confused between c and d

Answer 2

Only Option D will Give a Safe Sequence So only Option D will be RIght , and All remaining Option are Wrong.