Question

if a is subset of b .n(a)=4 n(b)=7 then n(a-b)​

Answer 1

n(a-b) =3

Step-by-step explanation:

n(a-b) =n(a)+n(b)-n(a+b,)

Answer 2

If $A\subset B$, $n(A)=4$, $n(B)=7$ then $n(A-B)=0$

Step-by-step explanation:

Given

$A\subset B$

$n(A)=4$

$n(B)=7$

Since, $A\subset B$

Therefore, all the elements of A are in B

We know that

$A-B$ represents all the elements in $A$ but not in $B$

Therefore,

$A-B=\phi$

Thus,

$n(A-B)=0$

Hope this answer is helpful.

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