Q3.The Gross Domestic Product (GDP) in Rupees grew at 7% during 2012-2013. For
international comparison, the GDP is compared in US Dollars (USD) after conversion based
on the market exchange rate. During the period 2012-2013 the exchange rate for the USD
increased from Rs. 50/ USD to Rs. 60/ USD. India’s GDP in USD during the period 2012-
2013
Answer : Option DExplaination / Solution:
Per 100 Rs final value 107 Rs
Q4.What is the optimized version of the relation algebra expression where
A1, A2 are sets of attributes in with A1 ⊂ A2 and F1, F2 are Boolean expressions based on
Answer : Option AExplaination / Solution: No Explaination.
Q5.A prime attribute of a relation scheme R is an attribute that appears
Answer : Option BExplaination / Solution:
A prime attribute or key attribute of a relation scheme R is an attribute that appears in any of
the candidate key of R, remaining attributes are known as non-prime or non-key tribute
Q7. Consider the relational schema given below, where eId of the relation dependentis a foreign
key referring to empId of the relation employee. Assume that every employee has at least one
associated dependent in the dependent relation.
employee (empId, empName, empAge)
dependent (depId, eId, depName, depAge)
Consider the following relational algebra query
The above query evaluates to the set of empIds of employees whose age is greater than that of
Answer : Option DExplaination / Solution:
Part A of the above given relational algebra query will give the set of empIds of those
employees whose age is less than or equal to the age of some of his/her dependents.
Now when set of empIds of all employees minus set of empIds obtained from part A is done,
then we get the set of empIds of employees whose age is greater than that of all of his/her
dependents.
Q8. Consider the decision problem 2CNFSAT defined as follows:
{ φ | φ is a satisfiable propositional formula in CNF with at most two literal per clause}
For example, is a Boolean formula and it is in 2CNFSAT.
The decision problem 2CNFSAT is
Answer : Option BExplaination / Solution:
2 SAT is in P. This we can prove by reducing 2 SAT to directed graph reachability problem
which is known to be in P.
Procedure for reducing 2 SAT to reachability problem:
1. Let ϕ be CNF with clauses of length 2 and let P be the set of propositional
variables(literals) in ϕ
2. Build a graph G=(V,E) with V= P { p|p P} ∪ ¬ ∈ and (x, y E )∈ iff there is a clause in ϕ
that is equivalent to x y → (all the clauses are converted to equivalent implications and
the graph built is called as implication graph)
3. Observe that ϕ is unsatisfiable iff there is a p P ∈ such that there is both a path from p to
to ¬p and from ¬p to p in G.
This condition can be tested by running the reachability algorithm several times.
Q9.Consider the following transaction involving two bank account x and y.
read (x) ; x : = x – 50; write (x) ; read (y); y : = y + 50 ; write (y)
The constraint that the sum of the accounts x and y should remain constant is that of
Answer : Option BExplaination / Solution:
The consistency property ensures that the database remains in a consistent state before the
(start of the transaction and after the transaction is over. Here sum of the accounts x & y
should remain same before & after execution of the given transactions which refers to the
consistency of the sum.
S1 : if a candidate is known to be corrupt, then he will not be elected
S2 : if a candidate is kind, he will be elected
Which one of the following statements follows from S1 and S2 per sound interference rules of
logic?
Answer : Option CExplaination / Solution:
Let P: candidate known to be corrupt
q: candidate will be elected
r: candidate is kind
S1 = p ⟶ ~ q
= q ⟶~p
S2 = r ⟶ q
i.e., If a person is kind, he is not known to be corrupt
Option is C
Total Question/Mark :
Scored Mark :
Mark for Correct Answer : 1
Mark for Wrong Answer : -0.5
Mark for Left Answer : 0