SSC CHSL 7 Mar 2018 Shift 1 Paper

Let the numbers be $\mathit{x},\mathit{y},\mathit{z}$
Thus, $\mathit{x}:\mathit{y}=5:7$ -----------(i) and $\mathit{y}:\mathit{x}=5:3$ -------------(ii)
Multiplying equation (i) by 5 and equation (ii) by 7
⇒ $\mathit{x}:\mathit{y}:\mathit{z}=25:35:21$
Let $\mathit{x}=25\mathit{k},\mathit{y}=35\mathit{k}\mathrm{and}\mathit{z}=21\mathit{k}$
⇒ Sum of three numbers = $25\mathit{k}+35\mathit{k}+21\mathit{k}=81\mathit{k}=162$
⇒ $\mathit{k}=\frac{162}{81}=2$
∴ Second number = $35\times 2=70$