Question

The set builder form of given set $A = \{3,6,9,12\}$ and $B = \{1,4, 9,...,\, 100\}$ is

• A. $A = \left\{x: x = 3n, \,n\, \in \,N\, \text{and} \,1 \le n \le 5\right\}$,
  $B = \left\{x: x = n^{2}, n \, \in \, N \,\text{and} \,1 \le n \le 10\right\}$
• B. $A = \left\{x: x = 3n, \,n\, \in \,N\, \text{and} \,1 \le n \le 4\right\}$,
  $B = \left\{x: x = n^{2}, n \, \in \, N \,\text{and} \,1 \le n \le 10\right\}$
• C. $A = \left\{x: x = 3n, \,n\, \in \,N\, \text{and} \,1 \le n \le 4\right\}$,
  $B = \left\{x: x = n^{2}, n \, \in \, N \,\text{and} \,1 < n < 10\right\}$
• D. None of these

Answer 1

Answer: (B)

Given, $A = \left\{3, \,6, \quad9, \quad12\right\}$
$= \left\{x: x = 3n, \,n\, \in \,N\, \text{and} \,1 \le n \le 4\right\}$
and $B = \left\{1,\,4,\,9,\,..., \,100\right\}$
$ = \left\{x: x = n^{2}, n \, \in \, N \,\text{and} \,1 \le n \le 10\right\}$