If X and Y are two sets such that X has 40 elements, `X uuY` has 60 elements and `X nnY` has 10 elements, how many elements does Y have?

Explanation

Given that,


`n(X)=40`

`n(uu∪Y)=60`

`n(XnnY)=10`

We know that

`n(XuuY)=n(X)+n(Y)–n(XnnY)`

`∴60=40+n(Y)–10`

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