Quantitative Aptitude Ques 2145
Question: If $ \frac{a}{b}+\frac{b}{a}=1, $ then the value of $ (a^{3}+b^{3}) $ is
Options:
A) 0
B) 1
C) 2
D) 3
Show Answer
Answer:
Correct Answer: A
Solution:
- Given, $ \frac{a}{b}+\frac{b}{a}=1 $
$ \Rightarrow $ $ \frac{a^{2}+b^{2}}{ab}=1 $
$ \Rightarrow $ $ a^{2}+b^{2}=ab $ (i) Now, $ a^{3}+b^{3}=(a^{2}+b^{2}-ab) $ $ =(a+b)(ab-ab) $ [from Eq.(i)] $ =(a+b)\cdot 0=0 $
BETA
