# CSE - Questions and solutions set-3

Computer science and engineering(CSE) - Question & solution set-3
Question:-
Option (A)
40 bits
Option (B)
80 bits
Option (C)
160 bits
Option (D)
180 bits
Correct Option:
C
Question Solution:
Let F = frame size
C = bit rate
I = propogation delaty and A = Ack Delay
The amount of time the sender spends sending one frame is F/C.
The total time before the next frame can be sent is F/C + I + A/C + I.

If we assume that ACKs are negligible, then to obtain an efficiency of 50 percent, we must have the following

```
F/C
--------- >= 1/2
F/C + 2I

or F/C >= F/2C + I
or F >= 2IC
or F >= 2(20 * 10-3)(4*103)
or F >= 160 bits
```
Question:-
Option (A)
1DF
Option (B)
1CF
Option (C)
DF1
Option (D)
DAC
Correct Option:
A
Question Solution:
In Direct Mapped cache, complete memory address range is divided by total cache size.
thus, if 0xFBFC is to be addressed then first divide it by 512*32 (cache size) and then remainder is mapped inside cache address.
0xFBFC % 512*32 = 0x3BFC

Now mapping 0x3BFC address inside 512 blocks will require to divide 0x3BFC by 32 will give address 0x1DF.
Question:-
Option (A)
7,8
Option (B)
19,20
Option (C)
18,17
Option (D)
17,18
Correct Option:
D
Question Solution:
Logical address space = 128 pages of 1024 words each => meaning 7 + 10 bits are required to adress whole space
Physical address space 256 frames of 1024 words each => meaning 8 + 10 bits are required to address whole space
Question:-
Option (A)
13
Option (B)
17
Option (C)
19
Option (D)
21
Correct Option:
A
Question:-
Option (A)
18750
Option (B)
20000
Option (C)
25000
Option (D)
Null
Correct Option:
C
Question Solution:
Because set 4 is NULL means not a supple at all.

new executes queries on remaining tree supple.

Average ={(15000+25000+35000)/3}=25000/-

Hence C is correct.

Question:-
Option (A)
Left-most derivatives.
Option (B)
Right-most derivatives.
Option (C)
Right-most derivatives in reverse.
Option (D)
Left-most derivatives in reverse.
Correct Option:
A
Question Solution:
Top down parser always generates left most derivatives.