MCQ
Choose the correct answer from the given four options.Consider the non-empty set consisting of children in a family and a relation $R$ defined as $\text{aRb}$ if a is brother of $b.$ Then $R$ is:
  • A
    Symmetric but not transitive.
  • Transitive but not symmetric.
  • C
    Neither symmetric nor transitive.
  • D
    Both symmetric and transitive.

Answer

Correct option: B.
Transitive but not symmetric.
We are given that a relation $R$ defined $\text{aRb} \Rightarrow a$ is brother of $b.$
$aRa \Rightarrow a$ is brother of $a,$ which is not true.
Hence$, R$ is not reflexive.
$aRb \Rightarrow a$ is brother of $b.$
This does not mean $b$ is also a brother of $a$ and $b$ can be a sister of $a.$
Hence, it is not symmetric.
$aRb \Rightarrow a$ is brother of $b$
and $bRc \Rightarrow b$ is a brother of $c.$
So$, a$ is brother of $c.$
Hence$, R$ is transitive.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

The ratio $h$ : $2 r$ for which $S$ to be minimum will be equal to
$\int_{\,0}^{\,\infty } {\,\log \left( {x + \frac{1}{x}} \right)\frac{{dx}}{{1 + {x^2}}}} $ is equal to
Let $M$ and $N$ be two $3 \times 3$ non-singular skew-symmetric matrices such that $M N=N M$. If $P^T$ denotes the transpose of $P$, then $M^2 N^2\left(M^T N\right)^{-1}\left(M N^{-1}\right)^T$ is equal to

$(A)$ $M^2$ $(B)$ $-N^2$ $(C)$ $-M^2$ $(D)$ $M N$

A line with positive direction cosines passes through the point $P(2, -1, 2)$ and makes equal angles with the coordinate axes. The line meets the plane $2x + y + z = 9$ at point $Q$. The length of the line segment $PQ$ equals :
Choose the correct answer from the given four options. Let $A = \{1, 2, 3, ...n\}$ and $B = {a, b}.$ Then the number of surjections from $A$ into $B$ is:
If area bounded by the curves $x = at^2$ and $y = ax^2$ is $1,$ then a $.......$
Let $A =$ $ \left[ {\begin{array}{*{20}{c}}1&2&2\\2&1&2\\2&2&1\end{array}}\right]$ , then
The domain of $\cos^{-1}\big(\text{x}^2-4\big)$ is:
Let $\vec{a}, \vec{b}$ and $\vec{c}$ be three non-zero non-coplanar vectors. Let the position vectors of four points $A, B, \quad C$ and $D$ be $\vec{a}-\vec{b}+\vec{c}, \lambda \vec{a}-3 \vec{b}+4 \vec{c}$, $-\vec{a}+2 \vec{b}-3 \vec{c}$ and $2 \vec{a}-4 \vec{b}+6 \vec{c}$ respectively. If $\overrightarrow{A B}$, $\overline{ AC }$ and $\overline{ AD }$ are coplanar, then $\lambda$ is :
The derivative of $\text{f(x)}=\int\limits^{\text{x}^3}_{\text{x}^2}\frac{1}{\log_{\text{e}}\text{t}}\text{ dt},(\text{x} > 0),$ is :