PREVIOUS YEAR SOLVED PAPERS MCQ - GATE 2017 Shift 1

51 Consider the language L given by the regular expression (a+b)*b(a+b) over the alphabet {a, b}. The smallest number of states needed in a deterministic finite-state automation (DFA) accepting L is ______.

Note – Numerical Type question

The regular expression can be described as “All strings over {a, b} ending with “ba” or “bb”. The minimal DFA accepting L is having 4 states:

52 Consider a two-level cache hierarchy with L1 and L2 caches. An application incurs 1.4 memory accesses per instruction on average. For this application, the miss rate of L1 cache 0.1, the L2 cache experiences, on average, 7 misses per 1000 instructions. The miss rate of L2 expressed correct to two decimal places is _____.

Note – Numerical Type question

Number of memory access in 1000 instructions = 1.4 x 1000
= 1,400
∴ Miss rate = 7/(1400 x 0.1) = 0.05

53 Consider the following CPU processes with arrival times (in milliseconds) and length of CPU bursts (in milliseconds) as given below:

Process	Arrival time	Burst time
P1	0	7
P2	3	3
P3	5	5
P4	6	2

If the pre-emptive shortest remaining time first scheduling algorithm is used to schedule the processes, then the average waiting time across all processes is _______ milliseconds.

Note: Numerical Type question.

Turn Around Time
P1 = 12-0 = 12
P2 = 6-3 = 3
P3 = 17-5 = 12
P4 = 8 - 6 = 2
Waiting Time
P1 = 12-7 = 5
P2 = 3-3 = 0
P3 = 12-5 = 7
P4 = 2 - 2 = 0
Average Waiting time = (7+0+5+0)/4 = 3.0
Therefore, option C is correct

54 Consider a database that has the relation schema EMP (EmpId, EmpName, and DeptName). An instance of the schema EMP and a SQL query on it are given below.

EMP
EmpId	Emp Name	Dept Name
1.	XYA	AA
2.	XYB	AA
3.	XYC	AA
4.	XYD	AA
5.	XYE	AB
6.	XYF	AB
7.	XYG	AB
8.	XYH	AC
9.	XYI	AC
10.	XYJ	AC
11.	XYK	AD
12.	XYL	AD
13.	XYM	AE

SELECT AVG (EC.Num)
FROM EC
WHERE(DeptName, Num)IN
(SELECT DeptName, COUNT(EmpId)AS
EC(DeptName,Num)
FROMEMP
GROUP BY DeptName)

The output of executing the SQL query is _____.

Note – Numerical Type question

EC
Dept Name	Num
AA	4
AB	3
AC	3
AD	2
AE	1

Avg(NUM) = 13/5 = 2.6

55 Let T be a tree with 10 vertices. The sum of the degrees of all the vertices in T is _____.

Note – Numerical Type question

Given, v= Total vertices = 10
e = v – 1 =9
Degree = 2 * e = 18
Therefore, option C is correct

PREVIOUS YEAR SOLVED PAPERS MCQ - GATE 2017 Shift 1

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