Topics

# If A = $$\Large \{ x : x = 4n+1, 2 \le n \le 5 \}$$ then number of subsets of A is:

 A) 16 B) 15 C) 4 D) none of these

 B) 15

Given that $$\Large A = \{ x:x=4n+1;\ 2 \le n \le 5 \}$$

Number of elements in set A is 4 ,

So, number of proper subsets = $$\Large 2^{4} - 1 = 15$$.

Part of solved Set theory questions and answers : >> Elementary Mathematics >> Set theory

Similar Questions
1). Let R and S be two relations on a set A. Then which is not correct?
 A). R and S are transitive, then R u S is also transitive. B). R and S are transitive, then R n S is also transitive. C). R and S are reflexive, then R n S is also reflexive. D). R and S are symmetric, then R U S is also symmetric
2). The group of beautiful girls is:
 A). a null set B). a finite set C). a singleton set D). not a set
3). R is a relation over the set of real numbers and it is given by $$\Large nm \ge 0$$. Then R is:
 A). symmetric and transitive B). reflexive and symmetric C). a partial order relation D). an equivalence relation
4). In a city of 55 students, the number of students studying different subjects are 23 in mathematics, 24 in physics, 19 in chemistry, 12 in mathematics and physics, 9 in mathematics and chemistry, 7 in physics and chemistry and 4 in all the three subjects. The number of students who have taken exactly one subject is:
 A). 6 B). 9 C). 7 D). all of these
5). If $$\Large N_{a}=\{ an : n \epsilon N \}$$, then $$\Large N_{3} \cap N_{4}$$ is equal to:
 A). $$\Large N_{7}$$ B). $$\Large N_{12}$$ C). $$\Large N_{3}$$ D). $$\Large N_{4}$$

6). The relation "Congruence modulo m" is:
 A). reflexive only B). transitive only C). symmetric only D). an equivalence relation
 A). $$\Large f:A \rightarrow B$$ B). $$\Large f:x \rightarrow f \left(x\right)$$ C). f is a mapping from A to B D). f is a function from A to B
 A). $$\Large A \cap B \subset A \cup B$$ B). $$\Large A \cap B \subseteq A \cup B$$ C). $$\Large A \cup B \subset A \cap B$$ D). None of these
10). Let $$\Large f:N \rightarrow R:f \left(x\right)=\frac{ \left(2x-1\right) }{2}$$ and $$\Large g:Q \rightarrow R:g \left(x\right)=x+2$$ be two functions then $$\Large \left(gof\right) \left(\frac{3}{2}\right)$$
 A). 3 B). 1 C). $$\Large \frac{7}{2}$$ D). None of these