Sets and relations

Question

If A is a set of positive odd elements less than 10. Then what is the cardinality of set A?

Comments

@shaik

thats what i did in my soln if thats the case than we need to take all such possibilities of sets..

@arjun sir

how you are looking at the question..please help.?

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How I look does not matter :) A good question will have only $1$ standard way

• $A$ is a set of positive odd numbers less than $10$
• $A = \{x \mid x \text{ is odd and }x < 10\}$

Both should mean the same and $\mid A \mid = 5$ as $A = \{1,3,5,7,9\}.$

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@arjun sir

ok..:) thanks.!

Answer 1

even though the question is answered, it is good enoug to trcik us.

If A is a set of positive odd elements less than 10. Then what is the cardinality of set A?

The set can be formed as {1,3,5,7,9}.

Cardinality is the number of elements in a set, clearly it is 5.

We might end up calculating power set and then calculating cardinality,but thats not the case.

Answer 2

https://en.wikipedia.org/wiki/Cardinality