NCERT Class XI Mathematics - Sets - Solutions
© examsnet.com
Question : 53
Total: 73
If S and T are two sets such that S has 21 elements, T has 32 elements, and S ∩ T has 11 elements, how many elements does S ∪ T have?
Solution:
Here n(S) = 21, n(T) = 32 and n(S ∩ T) = 11
We know that
n(S ∪ T) = n(S) + n(T) – n(S ∩ T)
∴ n(S ∪ T) = 21 + 32 – 11 = 42.
We know that
n(S ∪ T) = n(S) + n(T) – n(S ∩ T)
∴ n(S ∪ T) = 21 + 32 – 11 = 42.
© examsnet.com
Go to Question: