Tag: cartesian product of sets

Questions Related to cartesian product of sets

Let a relation $R$ be defined by $R=\left {(4,5), (1,4), (4,6), (7,6), (3,7)\right }$. The relation $R^{-1}\circ R$ is given by

  1. $\left {(1,1), (4,4), (7,4), (4,7), (7,7)\right }$

  2. $\left {(1,1), (4,4), (4,7), (7,4), (7,7),(3,3)\right }$

  3. $\left {(1,5), (1,6), (3,6)\right }$

  4. None of these


Correct Option: B
Explanation:
We have $R=\left \{(4,5), (1,4), (4,6), (7,6), (3,7)\right \}$.
$\therefore R^{-1}=\left \{(5,4), (4,1), (6,4), (6,7), (7,3)\right \}$
$(4,4)\in R^{-1}\circ R$ because $(4,5)\in R$ and $(5,4)\in R^{-1}$
$(1,1)\in R^{-1}\circ R$ because $(1,4)\in R$ and $(4,1)\in R^{-1}$
$(4,4)\in R^{-1}\circ R$ because $(4,6)\in R$ and $(6,4)\in R^{-1}$
$(4,7)\in R^{-1}\circ R$ because $(4,6)\in R$ and $(6,7)\in R^{-1}$
$(7,4)\in R^{-1}\circ R$ because $(7,6)\in R$ and $(6,4)\in R^{-1}$
$(7,7)\in R^{-1}\circ R$ because $(7,6)\in R$ and $(6,7)\in R^{-1}$
$(3,3)\in R^{-1}\circ R$ because $(3,7)\in R$ and $(7,3)\in R^{-1}$
$\therefore R^{-1}\circ R=\left \{(4,4), (1,1), (4,7), (7,4), (7,7), (3,3)\right \}$.
$\therefore$ The correct answer is $B$.

Given $(a - 2, b + 3) = (6, 8)$, are equal ordered pair. Find the value of $a$ and $b$.

  1. $a = 8$ and $b = 5$

  2. $a = 8$ and $b = 3$

  3. $a = 5$ and $b = 5$

  4. $a = 8$ and $b = 6$


Correct Option: A
Explanation:

By equality of ordered pairs, we have
$(a - 2, b + 3) = (6, 8)$
On equating we get
$a - 2 = 6$
$a = 8$
$b + 3 = 8$
$b = 5$
So, the value of$ a = 8 $ and $ b = 5.$

What is the second component of an ordered pair $(3, -0.2)$?

  1. $3$

  2. $0.2$

  3. $1$

  4. $-0.2$


Correct Option: D
Explanation:

In an ordered pair $(x,y)$, the first component is $x$ and the second component is $y$.

Therefore, in an ordered pair $(3,-0.2)$, the second component is $-0.2$.

What is the first component of an ordered pair $(1, -1)$?

  1. $1$

  2. $-1$

  3. $2$

  4. $0$


Correct Option: A
Explanation:

In an ordered pair $(x,y)$, the first component is $x$ and the second component is $y$.

Therefore, in an ordered pair $(1,-1)$, the first component is $1$.

Ordered pairs $(x, y)$ and $(-1, -1)$ are equal if $y = -1$ and $x =$ _____

  1. $1$

  2. $-1$

  3. $0$

  4. $2$


Correct Option: B
Explanation:

Given , $(x-y)=(-1,1)$

$x=-1, y=-1$
The value of $x=-1$.

Ordered pairs $(x, y)$ and $(3, 6)$ are equal if $x = 3$ and $y = ?$

  1. $3$

  2. $6$

  3. $-6$

  4. $-3$


Correct Option: B
Explanation:

Given 

$(x,y)= (3,6)$
$x=3$
$y=6$
The value of $x=3$ and $y=6$.

If $A \times B = {(3, a), (3, -1), (3, 0), (5, a), (5, -1), (5, 0)}$, find $A$.

  1. ${a, 5}$

  2. ${a, -1}$

  3. ${0, 5}$

  4. ${3, 5}$


Correct Option: D
Explanation:

$A\times B = {(3,a),(3,-1),(3,0),(5,a),(5,-1),(5,0)}$

$A={3,5}$
as we know A is set of all entries in ordered  pair $A\times B$.

$(x, y)$ and $(p, q)$ are two ordered pairs. Find the values of $x$ and $p$, if $(3x - 1, 9) = (11, p + 2)$

  1. $x = 4, p = 9$

  2. $x = 6, p = 7$

  3. $x = 4, p = 5$

  4. $x = 4, p = 7$


Correct Option: D
Explanation:

Given$(x,y)=(p,q)$
$(3x - 1, 9) = (11, p + 2)$
By equating 
$3x - 1 = 11$
$3x = 12$
$x = 4$
$9 = p + 2$
$p = 7$
So, the value of $x = 4, p = 7.$

 $(x, y)$ and $(p, q)$ are two ordered pairs. Find the values of $p$ and $y$, if $(4y + 5, 3p - 1) = (25, p + 1)$

  1. $p = 0, y = 5$

  2. $p = 1, y = 5$

  3. $p = 0, y = 1$

  4. $p = 1, y = 1$


Correct Option: B
Explanation:

Given $(x,y)=(p,q)$
$(4y + 5, 3p - 1) = (25, p + 1)$
On equating we get
$4y + 5 = 25$
$4y = 25 - 5$
$4y = 20$
$y = 5$
$3p - 1 = p + 1$
$3p - p = 1 + 1$
$2p = 2$
$p = 1$
So, the value of$ p = 1, y = 5$

If $A = {2, 3}$ and $B = {1, 2}$, find $A \times B$.

  1. ${(2, 1), (2, 2), (3, 1), (3, 2)}$

  2. ${(2, 1), (2, 1), (3, 1), (3, 2)}$

  3. ${(2, 1), (2, 2), (2, 1), (3, 2)}$

  4. ${2, 1), (2, 2), (3, 1), (2, 2)}$


Correct Option: A
Explanation:

$A= {2,3}$

$B={1,2}$
$A\times B = {2,3} \times {1,2}$
$={(2,1),(2,2),(3,1),(3,2)}$