RRB NTPC Prelims Model Paper 4 with solutions

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Question : 60 of 100

Marks: +1, -0

If the sum of

a /b

and its reciprocal is 1 and a ≠ 0, b ≠ 0, then the value of

a^3 + b^3

is

2
−1
0
1

Solution:

(3) Since,

a/b+b/a=1

⇒a^2+b^2=ab

⇒a^2+b^2-ab=0

Therefore,

a^3 +b3 =(a +b)(a^2 +b^2 -ab) =0

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