Question

What is the cardinal number of following sets?

$P=\left\{planetsinoursolarsystem\right\}$

Answer 1

The number of distinct elements in a finite set is called the cardinal number of the set. It is denoted by $n\left(P\right)$

Given set:

$P=\left\{planetsinoursolarsystem\right\}$

Name of planets in our solar system is $\left\{Mercury,Venus,Earth,Mars,Jupiter,Saturn,Uranus,Neptune\right\}$

As it can be seen that we have total $8$ planets in solar system.

Hence, the cardinal number of the set $P=\left\{planetsinoursolarsystem\right\}$ is $n\left(P\right)=8$