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IBPS RRB Office Assistant 2018 Paper
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© examsnet.com
Question : 42
Total: 80
If
A
2
−
B
2
=
252
and
A
+
B
=
42
, then find the value of B.
18
16
14
20
22
Validate
Solution:
Given,
A
2
−
B
2
=
252
... (i)
and A + B = 42 ...(ii)
From Eq. (i)
⇒
(
A
+
B
)
(
A
−
B
)
=
252
[
∵
A
2
−
B
2
=
(
A
+
B
)
(
A
−
B
)
]
⇒ 42 x (A - B) = 252
[∵ put the value of A + B]
⇒
A
−
B
=
252
42
A - B = 6 ...(iii)
Subtracting Eq. (iii) from Eq. (ii),
2B = 36 ⇒ B = 18
© examsnet.com
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