A) 5
B) \[-5\]
C) 4
D) \[-7\]
E) \[-4\]
Correct Answer: E
Solution :
We have \[a*b=\frac{a}{a+b}\] \[\Rightarrow \] \[\frac{1}{a*b}=\frac{a+b}{a}=1+\frac{b}{a}\] \[\Rightarrow \] \[\frac{1}{5}=1+\frac{b}{a}\] \[\Rightarrow \] \[\frac{b}{a}=-\frac{4}{5}\] \[\Rightarrow \] \[\frac{a}{b}=-\frac{5}{4}\] Now, \[\frac{1}{b*a}=\frac{b+a}{b}=1+\frac{a}{b}\] \[=1-\frac{5}{4}=-\frac{1}{4}\] \[\Rightarrow \] \[b*a=-4\]You need to login to perform this action.
You will be redirected in
3 sec