Download App

Sets — Maths STD 11 Science — Question

CBSE BoardEnglish MediumSTD 11 ScienceMathsSets1 Mark
MCQ
Let $\ce{n(A) = 28, n(A ∩ B) = 8, n(A ∪ B)} = 52,$ then $\ce{n(A ∩ B′)} =.$
  • A
    $30$
  • B
    $32$
  • ✓
    $20$
  • D
    none of these.
✓

Answer

Correct option: C.
$20$
Given $\ce{n(A) = 28, n(A ∩ B)} = 8.$
We have $\ce{A ∩ B′ = A − A ∩ B.}$
This give $\ce{n(A ∩ B′) = n(A) − n(A ∩ B)}$
or, $\ce{n(A ∩ B′)} = 28 − 8 = 20.$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from Sets→Sets — all question types→Maths STD 11 Science question papers→CBSE Board STD 11 Science question papers→CBSE Board question paper generator→

Similar questions

In an isosceles triangle $ABC$, the vertex $A$ is $(6,1)$ and the equation of the base $BC$ is $2 x + y =4$. Let the point $B$ lie on the line $x+3 y=7$. If $(\alpha, \beta)$ is the centroid $\triangle A B C$, then $15(\alpha+\beta)$ is equal to
→
The equations of the common tangents to the ellipse, $ x^2 + 4y^2 = 8 $ $\&$  the parabola $y^2 = 4x$  can be
→
$\frac{{\tan A + \sec A - 1}}{{\tan A - \sec A + 1}} = $
→
Mean of variable series $\bar{x}=773$ and mean deviation $64.4,$ then coefficient of mean deviation is :
→
Three normals to the parabola ${y^2} = x$ are drawn through a point $(C, 0)$, then
→
$\mathop {\lim }\limits_{x \to 0} \frac{{{{\sin }^{ - 1}}x - {{\tan }^{ - 1}}x}}{{{x^3}}}$ is equal to
→
A tangent to a hyperbola $\frac{{{x^2}}}{{{a^2}}} - \frac{{{y^2}}}{{{b^2}}} = 1$ intercepts a length of unity from each of the co-ordinate axes, then the point $(a, b)$ lies on the rectangular hyperbola
→
Let $\mathrm{f}: \mathrm{R} \rightarrow \mathrm{R}$ be a function such that $\mathrm{f}(2)=4$ and $\mathrm{f}^{\prime}(2)=1$. Then, the value of $\lim _{x \rightarrow 2} \frac{x^{2} f(2)-4 f(x)}{x-2}$ is equal to:
→
The number of arrangements of the letters of the word $CALCUTTA$
→
In a moderately asymmetrical distribution the mode and mean are $7$ and $4$ respectively. The median is
→