Tag: validating statements

Questions Related to validating statements

Tell if the following statement is true or false. In case give a valid reason for saying so
$p:$ If $x$ and $y$ are integers such that $x>y$. then $-x<-y$.

  1. True

  2. False


Correct Option: A
Explanation:

Given $x>y$


Multiply both sides by $-1$

$-x<-y$ $\therefore$ both statements true.

If p and q are mathematical statements, then in order to show that the statement p and q is true, we need to show that:

  1. The statement p is true and the statement q is not true

  2. The statement p is false and the statement q is true.

  3. The statement p is true and the statement q is false

  4. The statement p is true and the statement q is true


Correct Option: D

The component statements are:

p: You are wet when it rains.

q: You are wet when you are in river.

The compound statement of these component statements using appropriate connective is:

  1. You are not wet when you are in river or it rains.

  2. You are wet when you are in river and it rains.

  3. You are wet when it rains and you are in a river

  4. You are wet when it rains or you are in a river.


Correct Option: D

Two pairs of statement are:
p: If a quadrilateral is a rectangle, then its opposite sides are equal.
q: If opposite sides of a quadrilateral are equal, then the quadrilateral is a rectangle.
The combined statement of these pairs using If and only if is:

  1. A quadrilateral is a rectangle if and only if its all sides are equal.

  2. A quadrilateral is a rectangle if and only if its opposite sides are equal.

  3. A quadrilateral is a square if and only if its opposite sides are equal.

  4. A quadrilateral is not a rectangle if and only if its opposite sides are equal.


Correct Option: B

Name the technique used in the first step of the solution to the problem below :
Verify that 5 is irrational
Solution : Let us assume that 5 is rational

  1. Counter example

  2. Direct method

  3. By Contradiction

  4. Contrapositive method


Correct Option: C

Name the technique used in the solution of the problems below :

Question: Show that the following statement is false: If n is an odd integer, then n is prime.

Solution: The given statement is in the form “if p then q” we have to show that this is false, If p then ~q.


If n= 99 is odd integer which is not a prime number. Thus, we conclude that the given statement is false.

  1. Counter example

  2. Contrapositive method

  3. Direct method

  4. By Contradiction


Correct Option: A