Tag: implications

Questions Related to implications

$p:$ He is hard working.
$q:$ He will win.
The symbolic form of "If he will not win then he is not hard working", is

  1. $ p\Rightarrow q$

  2. $ (\sim p)\Rightarrow (\sim q)$

  3. $ (\sim q)\Rightarrow (\sim p)$

  4. $ (\sim q)\Rightarrow p$


Correct Option: C
Explanation:

Given $p:$ He is hard working

and $q:$ He will win
we get $\sim p:$ He is not hard working

and $\sim q:$ He will not win
Now the given statement in the question is "If he will not win then he is not hard working" which means 
"If he will not win then he is not hard working"
For this conditional statement, the symbolic form is $\left( \sim q \right) \Rightarrow \left( \sim p \right) $

Simplify $(p\vee q)\wedge(p\vee\sim q)$

  1. $p$

  2. $\sim p$

  3. $\sim q$

  4. $q$


Correct Option: A
Explanation:

$(p\vee q)\wedge (p\vee \sim q)$
$=p\vee(q\wedge \sim q)$ (distributive law)
$=p\vee 0$ (complement law)
$=p$ ($0$ is indentity for v)

The negation of the statement "No slow learners attend this school," is:

  1. All slow learners attend this school.

  2. All slow learners do not attend this school.

  3. Some slow learners attend this school.

  4. Some slow learners do not attend this school.

  5. No slow learners do not attend this school.


Correct Option: C
Explanation:

The negation is : It is false that no slow learners attend this school. Therefore, some slow learners attend this school.

Dual of $( p \rightarrow q ) \rightarrow r$ is _________________.

  1. $p\vee (\sim  q\wedge r)$

  2. $p\vee q\wedge r$

  3. $p\vee (\sim  q\wedge \sim r)$

  4. $\sim p\vee (\sim q\wedge r)$


Correct Option: A

The proposition $(p\rightarrow \sim p)\wedge (\sim p\rightarrow p)$ is a

  1. tautology.

  2. contradiction.

  3. neither a tautology nor a contradiction.

  4. tautology and contradiction.


Correct Option: B
Explanation:

 $p$ $\sim p $  $p\rightarrow \sim p $ $\sim p \rightarrow p$  $(p\rightarrow \sim p) \wedge(\sim p\rightarrow p)$ 

A contradiction.

Negation of the statement $p:\dfrac {1}{2}$ is rational and $\sqrt {3}$ is irrational is

  1. $\dfrac {1}{2}$ is rational or $\sqrt {3}$ is irrational

  2. $\dfrac {1}{2}$ is not rational or $\sqrt {3}$ is not irrational

  3. $\dfrac {1}{2}$ is not rational or $\sqrt {3}$ is irrational

  4. $\dfrac {1}{2}$ is rational and $\sqrt {3}$ is irrational


Correct Option: A

P: he studies hard, q: he will get good marks. The symbolic form of " If he studies hard then he will get good marks "is_____

  1. $\sim q\Rightarrow p$

  2. $p\Rightarrow q$

  3. $\sim p\vee q$

  4. $p\Leftrightarrow q$


Correct Option: B

Disjunction of two statements p and q is denoted by

  1. $p \leftrightarrow q$

  2. $p \rightarrow q$

  3. $p \leftarrow q$

  4. $p \vee q$


Correct Option: D

An implication or conditional "if p then q "is denoted by

  1. $p \vee q$

  2. $p \rightarrow q$

  3. $p \leftarrow q$

  4. None of these


Correct Option: B

The truth values of p, q and r for which $(pq)(∼r)$ has truth value F are respectively

  1. F, T, F

  2. F, F, F

  3. T, T, T

  4. T, F, F


Correct Option: C