Set Theory


Q31.

Which of the following is TRUE?
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Q32.

We are given a set X=\{x_{1},...,x_{n}\} where x_{i}=2^{i}. A sample S\subseteq X is drawn by selecting each x_{i} independently with probability p_{i}=\frac{1}{2}. The expected value of the smallest number in sample S is:
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Q33.

Let A be a set with n elements. Let C be a collection of distinct subsets of A such that for any two subsets S_1 and S_2 in C, either S_1 \subset S_2 or S_2\subset S_1. What is the maximum cardinality of C?
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Q34.

Let S={1,2,3....,m},m \gt 3. Let X_{1},...,X_{n} be subsets of S each of size 3. Define a function f from S to the set of natural numbers as, f(i) is the number of sets X_{j} that contain the element i. That is f(i)=|\{j|i\in X_{j}\}|. Then \sum_{i=1}^{m}f(i)
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Q35.

Let A, B and C be non-empty sets and let X = (A - B) - C and Y = (A - C) - (B - C) Which one of the following is TRUE?
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Q36.

Let n = p^{2}q, where p and q are distinct prime numbers. How many numbers m satisfy 1 \leq m \leq n and gcd(m,n)=1? Note that gcd(m,n) is the greatest common divisor of m and n.
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Q37.

Let E,F and G be finite sets. Let X=(E \capF) - (F\capG) and Y = (E - (E\capG)) - (E - F). Which one of the following is true?
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Q38.

In a class of 200 students, 125 students have taken Programming Language course, 85 students have taken Data Structures course, 65 students have taken Computer Organization course; 50 students have taken both Programming Language and Data Structures, 35 students have taken both Programming Language and Computer Organization; 30 students have taken both Data Structures and Computer Organization, 15 students have taken all the three courses. How many students have not taken any of the three courses?
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Q39.

A partial order \leq is defined on the set S=\left \{ x, a_1, a_2, \ldots, a_n, y \right \} \text{ as }x \leq _{i} a_{i} for all i and a_{i}\leq y for all i, where n \geq 1. The number of total orders on the set S which contain the partial order \leq is
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Q40.

Let X, Y, Z be sets of sizes x, y and z respectively. Let W=X\timesY and E be the set of all subsets of W. The number of functions from Z to E is
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