SSC CGL 23 Aug 2021 Shift 2 Paper

Let monthly salary of $\mathit{A}$ and $\mathit{B}$ be $\mathit{₹}\mathit{x}$.
According to the question, $\Rightarrow \frac{10\mathit{x}}{100}-\frac{7\mathit{x}}{100}=900$
$\Rightarrow 3\mathit{x}=900\times 100$
$\Rightarrow \mathit{x}=\mathit{₹}30000$
The monthly salary of $\mathit{A}=\mathit{B}=\mathit{₹}30000$
Let montly salary of $\mathit{C}$ is $\mathit{₹}\mathit{y}$.
Total donation by $\mathit{A}$ and $\mathit{B}$ is 600 more than of $\mathit{C}$. (given in question)
Now, donation given by $\mathit{A}=10\%$ of $30000=\mathit{₹}3000$
and donation given by $\mathit{B}=7\%$ of
$30000=\mathit{₹}2100$
Total donation $=\mathit{₹}5100$
Again, according to the question,
So, the monthly salary of $\mathit{y}$ is $\mathit{₹}50000$.