1
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

There are n white and n black balls marked 1, 2, 3, ...... n. The number of ways in which we can arrange these balls in a row so that neighbouring balls are of different colours is

A
(n!)2
B
(2n)!
C
2(n!)2
D
$${{(2n)!} \over {{{(n!)}^2}}}$$
2
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Let $$f(n) = {2^{n + 1}}$$, $$g(n) = 1 + (n + 1){2^n}$$ for all $$n \in N$$. Then

A
$$f(n) > g(n)$$
B
$$f(n) < g(n)$$
C
f(n) and g(n) are not comparable.
D
$$f(n) > g(n)$$ if n be even and $$f(n) < g(n)$$ if n be odd.
3
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

A is a set containing n elements. P and Q are two subsets of A. Then the number of ways of choosing P and Q so that P $$\cap$$ Q = $$\varphi $$ is

A
$${2^{2n\_2n}}{C_n}$$
B
$${2^n}$$
C
$${3^n} - 1$$
D
$${3^n}$$
4
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Under which of the following condition(s) does(do) the system of equations $$\left( {\matrix{ 1 & 2 & 4 \cr 2 & 1 & 2 \cr 1 & 2 & {(a - 4)} \cr } } \right)\left( {\matrix{ x \cr y \cr z \cr } } \right) = \left( {\matrix{ 6 \cr 4 \cr a \cr } } \right)$$ possesses(possess) unique solution ?

A
$$\forall$$ a $$\in$$ R
B
a = 8
C
for all integral values of a
D
a $$\ne$$ 8
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