Correct Answer - A
(a)
Given
P
(
A
∪
B
)
=
P
(
A
∩
B
)
Given
P
(
A
)
+
P
(
B
)
−
P
(
A
∩
B
)
=
P
(
A
∩
B
)
P
⇒
[
P
(
A
)
−
P
(
A
∩
B
)
]
+
[
P
(
B
)
−
P
(
A
∩
B
)
]
=
0
⇒
But
P
(
A
)
−
P
(
A
∩
B
)
≥
=
0
But
and
P
(
B
)
−
P
(
A
∩
B
)
≥
=
0
[
∵
P
(
A
∩
B
)
≤
P
(
A
)
or
P
(
B
)
]
and
⇒
P
(
A
)
−
P
(
A
∩
B
)
=
0
⇒
and
P
(
B
)
−
P
(
A
∩
B
)
=
0
and
[
since, sum of two non-negative numbers can be zero only when these numbers aree zero
]
[
⇒
P
(
A
)
=
P
(
A
∩
B
)
⇒
and
P
(
B
)
=
P
(
A
∩
B
)
and
∴
P
(
A
)
=
P
(
B
)
∴