Let A = \-2, -1, 0, 1, 2, 3\. Let R be a relation on A defined by xRy if and only if y = \x, 1\. Let l be the number of elements in R. Let m and n be the minimum number of elements required to be added in R to make it reflexive and symmetric relations, respectively. Then l + m + n is equal to
- 11
- 12
- 14
- 13
Answer
(2) 12
Solution
R = \(-2, 1), (-1, 1), (0, 1), (1, 1), (2, 2), (3, 3)\
l = 6
Reflexive: (1, 1), (2, 2), (3, 3) are present; add (-2, -2), (-1, -1), (0, 0)
m = 3
Symmetric: add the reverses of (-2, 1), (-1, 1), (0, 1), i.e. (1, -2), (1, -1), (1, 0)
n = 3
l + m + n = 6 + 3 + 3 = 12
Answer: (2)