Saturday, 5 November 2016

Mock Test with Answers

Due care has been taken for providing correct Answer-Keys, however, any kind of discussion is always welcome!

Section-I
Q.No. 1 to Q.No. 25 carry 1 mark each

1. Two numbers A and B are represented in signed 2’s complement form as A= 11101101 and B= 11100110. If B is subtracted from A, the value obtained in 2’s complement form is:
(a) 100000111
(b) 00000111
(c) 11111001
(d) 111111001

Ans: (B)

2. Which of the following is true about page size in virtual memory system:
S1: Small sized pages have larger internal fragmentation.
S2: Large sized pages have smaller page table but large management overhead.
S3: There is more continuous data available in larger pages.
(a) S1 and S2 only
(b) S2 and S3 only
(c) S3 only
(d) S1, S2, and S3

Ans: (C)

3. The overhead required to read an entry from a page table is 60 ns. To reduce this overhead, the computer has an associative memory that can hold 16 entries and can be accessed in 10 ns. What hit ratio is needed to reduce Effective Memory Access Time (EMAT) to 70 ns? (In percentage)
(a) 80%
(b) 70%
(c) 60%
(d) 75%

Ans: (A)

4. What is the bucket size, when the overlapping and collision occur at the same time?
(a) One
(b) Two
(c) Three
(d) Four

Ans: (A)

5. What is the largest number of key comparisons made by binary search in searching for a key in the following array?
3
14
27
31
39
42
55
70
74
81
85
93
98
  
(a) 4
(b) 5
(c) 6
(d) None of these

Ans: (A)

6. Consider a memory system with 1 MB of available memory requests for 42 kb, 10 kb and 28 kb. Calculate the amount of internal fragmentation in kb during this scenario using buddy allocation?
(a) 400 kb
(b) 148 kb
(c) 476 kb
(d) None of these

Ans: (B)

7. Spurious tables may occur due to
(i) Bad normalization
(ii) Theta joins
(iii) Updating tables from join
(a) Only (i) and (ii)
(b) Only (ii) and (iii)
(c) Only (i) and (iii)
(d) (i), (ii) and (iii)

Ans: (A)

8. A dominant entity is the entity
(a) On the N side in a 1:N relationship
(b) On the 1 side of a 1: N relationship
(c) On either side of a 1:1 relationship
(d) Nothing to do with 1:1 or 1:N relationship

Ans: (B)

9.  Ten thousand airline stations are competing for the use of a single slotted ALOHA channel. The average station makes 18 requests/hour. A slot is of 125 micro-sec. What is the approximate total channel load?
(a) 0.0125 requests/slot
(b) 0.0375 requests/slot
(c) 0.0345 requests/slot
(d) 0.0625 requests/slot

Ans: (D)

10. The real function f(z) = z|z| is differentiable at:
(a) at z= 0 only
(b) Everywhere
(c) Everywhere except at z=0
(d) Nowhere

Ans: (B)

11. Which of the following is false?
(a) The set  Σ* is countably infinite
(b) The set of decidable languages is countably infinite
(c) The set of recursively enumerable language is countably infinite
(d) The set of undecidable languages is countably infinite

Ans: (D)

12. Which of the following is the complement of function F= x(y’z’ + yz)
(a) x + yz’ + y’z’
(b) x’ + yz’ + y’z
(c) x’ + y’z’ + yz
(d) None of these

Ans: (B)

13. The minimum number of gates required to implement the Boolean expression
A’B’ + AB + A’C + A’C’ + B’C’ + B’C + B + C’ + C
(a) 2 NAND and 1 NOR gate
(b) 3 NAND gates
(c) 1 NAND and 1 OR gate
(d) None of these

Ans: (D)

14. For a 3-ary tree (each node can have maximum of 3 children). What is the maximum possible height with 50 nodes?
(a) 47
(b) 49
(c) 45
(d) None of these

Ans: (A)

15. Which of the following is used at high load situations?
(a) Pure ALOHA
(b) Slotted ALOHA
(c) Non-persistent CSMA
(d) Both (a) and (b)

Ans: (C)

16. The 8-bit character 10101111 is to be enclosed using odd parity Hamming code. What is the bit string that will be transmitted?
(a) 011101001111
(b) 001101011111
(c) 101101011111
(d) 011101011111

Ans: (D)

17. The mean time to failure is 30 seconds and the mean time to repair is 50 seconds. Calculate the mean time between failure.
(a) 30 seconds
(b) 80 seconds
(c) 20 seconds
(d) 50 seconds

Ans: (B)

18. Which of the following is the root of the equation cos x= 2x, correct upto 5 decimal places, by using Newton Raphson method?
(a) 0.50000
(b) 0.45063
(c) 0.45018
(d) 0.46000

Ans: (C)

19. The cycle graph Cn, n>=3 is a bipartite graph, for what values of n?
(a) n mod 3 =0
(b) n mod 5 =0
(c) n mod 2 =0
(d) n mod 2 = 1

Ans: (C)

20. A 4 bit synchronous counter uses flip-flops with propagation delay time of 20 ns each. The maximum possible time required to change of state will be:
(a) 20 ns
(b) 40 ns
(c) 60 ns
(d) 80 ns

Ans: (A)

21. An assembly language application contains 1200 assembly language instructions. It takes 12 seconds to run on benchmark. The application programmer then works on the assembly language code to make it better. After this the application takes 10 seconds to run. Calculate the speedup:
(a) 2.4
(b) 5/6
(c) 1.2
(d) 1.0

Ans: (C)

22. How many queues are required to implement the priority queue?
(a) 0
(b) 1
(c) 2
(d) Not possible to implement priority queue from a queue

Ans: (C)

23. Which of the following data structures is efficient considering space and time complexities?
(a) Incomplete binary tree
(b) Complete binary tree
(c) Full binary tree
(d) All given data structures have same complexities

Ans: (B)

24. Which of the following components is responsible for loading the initial value in the program counter for an application program before it starts running?
(a) Compiler
(b) Linker
(c) Loader
(d) Boot module or boot ROM

Ans: (C)

25. Table derived from the Entity Relationship Diagrams (ERD)
(a) Are always in 1NF
(b) Are totally un-normalized
(c) Can be further normalized
(d) May have multi-valued attributes  

Ans: (A)

Q.No. 26 to Q.No. 55 carry 2 marks each

26. Three squares are chosen randomly on a chessboard. What is the probability that all three are in the same direction? (There are two diagonals on a chessboard)
(a) 1/112
(b) 1/364
(c) 1/64
(d) 1/372

Ans: (D)

27. Ten coins are tossed one by one. In how many outcomes will the third coin turns up a head?
(a) 210
(b) 29
(c) 3 X 28
(d) 3 X 29

Ans: (B)

28. If G is a connected simple 3-regular planar graph in which every face is bounded by exactly 3 edges, then the size of the graph G is:
(a) 3
(b) 4
(c) 5
(d) None of these

Ans: (D)

29. Which of the following is not a CFL?
(a) { anbmcp | n=m or m=p}
(b) { anbmcp | n!=m or m!=p}
(c) { ambmcp | 2m <= p<=m}
(d) { ambn | m>=3n +5 or n<=2m +4}

Ans: (C)

30. The minimum number of NOT gates required to construct this logic expression?
F= (ABC)’ + (AB)’C + A’BC’ + A(BC)’ + AB’C
(a) 1
(b) 2
(c) 3
(d) 4

Ans: (C)

31. A computer system has the page size = 1024 Bytes and maintains the page table for each process in main memory. The overhead required for doing a lookup in page table is 500 ns. To reduce this overhead, the computer has a TLB that caches 32 virtual pages to physical frame mappings. A TLB lookup requires 100 ns. What TLB hit rate is required to ensure an average virtual address translation time of 200 ns?
(a) 0.250
(b) 0.375
(c) 0.625
(d) 0.750

Ans: (D)

32. Consider the C code below:
main ()
{
                char s[] = { ‘a’, ‘b’, ‘c’, ‘\n’, ‘c’, ‘\0’};
                char *p, *str, *str1;
                p = &s[3];
                str= p;
                str1=s;
                printf(“%d”, ++*p+++*str1-32);
}
What should be the output of the program?
(a) 77
(b) 78
(c) Compilation error
(d) None of these

Ans: (A)

33. A program experiences 400 expected faults. It takes into consideration that one fault leads to two failures. The initial failure intensity was 5 failures/CPU hour. Initially the failure intensity objective of 25 failures/100 CPU hours. Calculate the number of failures expected before release:
(a) 120
(b) 40
(c) 60
(d) 80

Ans: (B)

Common Data Question for 34 and 35:

·         Suppose that we have a disk with following parameters:
·         ·         1 TB in size
·         ·         7200 RPM, data transfer rate of 40 MBPS
·         ·         Average seek time of 6 ms
·         ·         ATA controller with 2 ms controller initiation time
·         ·         A block size of 4 KB.

34.   What is the transfer time for a random block to move from the disk in milliseconds?
(a) 0.368
(b) 0.256
(c) 1.024
(d) None of these

Ans: (D)

35. What is the average access time to read a random block from the disk in ms?
(a) 10.269
(b) 12.269
(c) 13.348
(d) None of these

Ans: (B)

36. There are six boxes numbered as 1, 2,....,6. Each box is to be filled up either with a red or a green ball in such a way that at least 1 box contains a green ball and the boxes containing green balls are consecutively numbered. The total number of ways in which this can be done:
(a) 5
(b) 21
(c) 33
(d) 60

Ans: (B)

37. Calculate the DMA data transfer rate of a 16 bit DMA device. DMA device is operating in cycle stealing mode. Each DMA cycle is of 16 clock states and DMA clock is 4 MHz. The intermediate CPU machine cycle takes 4 micro-seconds.
(a) 166 KBPS
(b) 200 Bytes/sec
(c) 217.77 KBPS
(d) 250 KBPS

Ans: (D)

38. Calculate the number of nodes in B-tree of order 5 after inserting
A g f b k d h m j e s i r x c l n t u p
Into an initially empty tree:
(a) 7
(b) 8
(c) 9
(d) None of these

Ans: (C)

39. Consider the processes listed below. Assume the arrival times to be zero.
Process
Burst Time
Priority
P1
3
1
P2
7
2
P3
2
2
P4
4
4
P5
1
3

Which of the following algorithm results in the minimum average waiting time for all processes?
(a) FCFS
(b) SJF
(c) Non-preemptive priority
(d) Round Robin with time quantum= 1

Ans: (B)

40. Consider a Unix file system with 12 direct pointers, 1 indirect pointer, 1 double indirect pointer and 1 triple indirect pointer in the i-node. Assume that disk blocks require 4 Bytes. How many disk reads will this file system require to read block 14 of the file named /a?
(a) 5 reads
(b) 11 reads
(c) 15 reads
(d) 17 reads

Ans: (A)

41. Consider the schedule given below:
S= R2(B) R1(A) W1(C) W1(B) R4(B) W3(A) R4(C) W2(D) R2(B) W4(A) W4(B)
Which of the following is true about the given schedule?
(a) Serializable schedule with T1 => T2
(b) Serializable schedule with T1=> T4
(c) Non-serializable schedule
(d) None of these

Ans: (C)

42.  System X uses stop n wait automatic repeat request protocol to send packets to system Y. If the distance between X and Y is 8000 km. Assume time between receiving and sending of ACK to be zero. Speed of propagation is speed of light. Calculate the time taken by system X to send out a packet of size 1000 Bytes, if throughput is 800000 KBPS.
(a) 100 msec
(b) 10 msec
(c) 10 micro-sec
(d) None of these

Ans: (C)

43. Which of the following can be the beginning address of a block that contains 1024 addresses?
(a) 205.16.37.32
(b) 190.16.42.0
(c) 117.17.32.0
(d) 125.45.24.52

Ans: (C)

Common Data Question for 44 and 45

In a 32 bit machine we subdivide the virtual address into 4 segments as follows:
10-bit
8-bit
6-bit
8-bit

We use a 3-level page table such that the first 10-bits for the first level and so on.

44. What is the page size in such a system?
(a) 1024 Bytes
(b) 64 Bytes
(c) 256 Bytes
(d) 2048 Bytes

Ans: (C)

45. What is the size of a page table for a process that has 256k memory starting at address 0?
(a) 4096 Bytes
(b) 4274 Bytes
(c) 4608 Bytes
(d) 2148 Bytes

Ans: (C)

Linked Question 46 and 47

46. What will be the resulting postorder of the binary min-heap that results from inserting 4, 9, 3, 7, 2, 5, 8, 6 into an initially empty binary min-heap?
(a) 9 6 7 3 5 8 2 4
(b) 6 9 3 7 5 2 4
(c) 6 7 9 3 5 8 4 2
(d) None of these

Ans: (D)

47. What will be the preorder of resulting min heap on deleting 2 and 3 from the tree formed in Q. 46?
(a) 4 6 9 7 5 8
(b) 4 5 6 7 8 9
(c) 4 6 7 9 5 8
(d) None of these

Ans: (A)

48. Which of the following may be a tree?
I. A simple graph of 12 vertices with 4 vertices of degree 3, 3 vertices of degree 4 and 6 vertices of degree 1
II. A simple graph of 8 vertices with 3 vertices of degree 3 and 5 vertices of degree 1
(a) I only
(b) II only
(c) Both I and II
(d) None of them

Ans: (B)

49. The ratio of covering number to matching number in the wheel graph W5 is:
(a) 3/2
(b) 1
(c) 2/3
(d) 5/3

Ans: (B)

50. Consider the sequence of nodes in preorder and inorder respectively:
Preorder: G B Q A C K F P D E R H
Inorder: Q B K C F A G P E D H R
Calculate the height of binary tree after constructing binary tree of above preorder and inorder traversals.
(a) 3
(b) 4
(c) 5
(d) None of these

Ans: (B)

Linked Questions 51 and 52

51. Insert the following sequence of elements into an AVL tree, which is initially empty:
71, 41, 91, 51, 46, 61, 56, 53
What will be the postorder traversal of resulting AVL tree?
(a) 71, 41, 91, 51, 46, 61, 56, 53
(b) 41, 46, 51, 53, 56, 61, 71, 91
(c) 91, 71, 61, 56, 53, 51, 46, 41
(d) None of these

Ans: (D)

52. After deleting the element 41 from the AVL tree formed in the previous question, calculate the preorder traversal of the resulting tree:
(a) 46, 51, 53, 56, 61, 71, 91
(b) 91, 71, 61, 56, 53, 51, 46
(c) 56, 51, 46, 53, 71, 61, 91
(d) None of these

Ans: (C)

53.  In a database file the blocks are of 2000Bytes with no header. Records are of 200 Bytes of which 15 bytes are for key field. Pointer takes 10 bytes and the file consists of 15,000 records. Calculate the number of blocks required using dense index:
(a) 200 blocks
(b) 60 blocks
(c) 250 blocks
(d) 300 blocks

Ans: (C)

Common Data Question for 54 and 55

In classful addressing, the mask for each block is implicit. The mask for class A block is 255.0.0.0/8. The mask for class B block is 255.255.0.0/16. The mask for class C block is 255.255.255.0/24. On the other hand in classless addressing, when an address is given the block to which address belongs cannot be found unless we have the mask. The mask is given in CIDR notation with the number of 1’s in the mask.

54. Find the first address in the block, if one of the addresses is 140.120.84.24/20
(a) 140.120.84.24/27
(b) 140.120.80.24/20
(c) 140.120.80.0/27
(d) 140.120.80.0/27

Ans: (D)

55. Find the last address in the block if one of the addresses is 140.120.84.24/20
(a) 140.120.84.255/20
(b) 140.120.255.255/20
(c) 140.120.95.255/20
(d) None of these

Ans: (C)

Section-II (General Aptitude)

Q.No. 56 to Q.no. 60 carry 1 mark each

56. What is the next number in the series:
4, 6, 12, 18, 30, 42, 60, 72, 102, 108
(a) 138
(b) 128
(c) 118
(d) 148

Ans: (A)

57. The number of solutions of the equation 2a+b = 40, where a and b are positive integers and a<=b
(a) 7
(b) 13
(c) 14
(d) 18

Ans: (B)

58. Select the pair of wrongly spelt words from the given choices:
(a) Irascible: Surreptitious
(b) Proclivity: Vicissitude
(c) Lassitude: Imperturbable
(d) Munificient: Psusillanimous

Ans: (D)

59. In a class, 40% of the students enrolled for Math and 70% of students enrolled for Hindi. If 15% of the students enrolled for both Math and Hindi, what percent of the students of the class did not enrol for either of the courses?
(a) 5%
(b) 95%
(c) 0%
(d) None of these

Ans: (A)

60. In a group of horses and birds, the number of legs are 14 more than twice the number of heads. The number of horses is:
(a) 5
(b) 7
(c) 10
(d) 12

Ans: (B)

Q.No. 61 to Q.no. 65 carry 2 marks each

61. Consider a 8X8 chessboard, it contains 64 1 X 1 squares and one 8 X 8 square. What is the total number of all the n X n square for 1<= n <= 8? It contains
(a) 184
(b) 204
(c) 326
(d) 672

Ans: (B)

62. Two candles of the same height are lighted at the same time. The first consumed in 4 hours and the second in 3 hours. Assume that each candle burs at a constant rate, in how many hours after being lighted the first candle is twice the height of the second?
(a) ¾ hours
(b) 3/2 hours
(c) 2 hours
(d) 12/5 hours

Ans: (D)

63. Sum of square of two numbers X and Y is less or equal to 100. How many sets of integers solutions of X and Y are possible?
(a) 299
(b) 297
(c) 315
(d) None of these

Ans: (D)

64. There are 6 tasks and 6 students. Task 1 cannot be assigned to either student 1 or student 2. Task 2 must be assigned to either student 3 or student 4. Every student is to be assigned a task. In how many ways can the assignment be done?
(a) 180
(b) 192
(c) 360
(d) 144

Ans: (D)

65. The length, breadth and height of an office are in the ratio 3:2:1. If the breadth and height are halved while the length is doubled, then the total area of the four walls of the office will
(a) remain same
(b) decrease by 15%
(c) decrease by 18.75%
(d) decrease by 30%

Ans: (D)

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