JEE MATHEMATICS MCQ: SET THEORY

1 Easy

1 of 1

Application +4 | -1

Suppose

A_1, A_2, A_3, \ldots \ldots \ldots, A_{30}

are thirty sets each having 5 elements and

B_1, B_2, \ldots \ldots ., B_n

are

n

sets each with 3 elements. Let

\bigcup_{i=1}^{30} A_i=\bigcup_{j=1}^n B_j=S

and each elements of

S

belongs to exactly 10 of the

A_i^{\prime} s

and exactly 9 of the

B_j^{\prime} s

. Then

n

is equal to:

View answer and explanation

Correct option: C

Option C (45) is correct because it calculates the number of sets

B_j

needed to satisfy the given conditions regarding the number of elements and their occurrences in the sets.

More Questions from SET THEORY

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S

2 a_1 a_2 a_3 \ldots . . a_{2006}

a_1, a_2, a_3, \ldots ., a_{2006}

S

a N=\{a n: n \in N: b N=\{n b: n \in N\}

c N=\{c N: n \in N\}

b N \cap c N=d N

a, b, c \in N

b, c

A=\{x: x

\}

B=\{x: x

A-B

F(n)

n

[\mathrm{F}(20) \cap \mathrm{F}(16)] \subseteq \mathrm{F}(\mathrm{y})

40 \%

A, 20 \%

10 \%

C

A

C

4 \%

A

C

2 \%

A