ABC26GN3010 · Ratio and Proportion
Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: · Marks: · Difficulty:
If $x: y=7: 3$, then the value of $\frac{x y+y^{2}}{x^{2}-y^{2}}$ is
(a)$\frac{3}{4}$
(b)$\frac{4}{3}$
(c)$\frac{3}{7}$
(d)$\frac{7}{3}$
Answer
Explanation
$$\frac{x}{y}=\frac{7}{3} \Rightarrow \frac{x y+y^{2}}{x^{2}-y^{2}}=\frac{\left(\frac{x}{y}\right)+1}{\left(\frac{x^{2}}{y^{2}}\right)-1}=\frac{\frac{7}{3}+1}{\left(\frac{7}{3}\right)^{2}-1}=\frac{10}{3} \times \frac{9}{40}=\frac{3}{4}$$
Explanation as extracted from the printed page; notation may be imperfect.
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