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1.Set Theory
medium
यदि $A$ और $B$ दो समुच्चय इस प्रकार हैं कि $n(A) = 70$, $n(B) = 60$ तथा $n(A \cup B) = 110$, तब $n(A \cap B)$ बराबर हैं
A
$240$
B
$50$
C
$40$
D
$20$
Solution
$n(A \cup B) = n(A) + n(B) – n(A \cap B)$
$==> 110 = 70 + 60 -n(A \cap B)$
$\therefore $ $n(A \cap B) = 130 – 110 = 20$.
Standard 11
Mathematics
