Q42,paper 2.J13. A Boolean operator o is defined as follows :

1o1 = 1,

 1 o0 = 0,

0 o1=0

 and

0 o0 = 1

What will be the truth value of the expression (x oy)oz = x o(yoz) ?

(A) Always false

(B) Always true

(C) Sometimes true

(D) True when x, y, z are all true .

Answer B.

x	y	z	(x oy)oz = x o(yoz)	Result of expr.
0	0	0	1.0=0.1->0=0	T(0=0)
0	0	1	1.1=0.0->1=1	T
0	1	0	0.0=0.0->1=1	T
0	1	1	0.1=0.1->0=0	T
1	0	0	0.0=1.1->1=1	T
1	0	1	0.1=1.0->0=0	T
1	1	0	1.0=1.0->0=0	T
1	1	1	1.1=1.1	T