If 3 x-5 y=5 and x/(x+y)=5/7, then what is the value of 2 x y is · ABC26GN1051
Subject: General Aptitude · Chapter: Simplification
If $3 x-5 y=5$ and $\frac{x}{x+y}=\frac{5}{7}$, then what is the value of $2 x y$ is
(a)3
(b)4
(c)6
(d)9
(e)None of these
Answer
Answer (as printed): A
Explanation
$3 x-5 y=5 \quad \ldots(i)$ and $\frac{x}{x+y}=\frac{5}{7} \Rightarrow 7 x=5 x+5 y$ $$\Rightarrow \quad 2 x-5 y=0$$ Subtracting (ii) from (i), we get: $x=5$. Putting $x=5$ in (i), we get: $y=2$. So, $x-y=5-2=3$.
Explanation as extracted from the printed page; notation may be imperfect.