BA LLB Banaras Hindu University 2019 Solved Paper

Let the number of 20 paisa coins be $\mathit{x}$ and 25 paisa coins be $\mathit{y}$
$\therefore \mathit{x}+\mathit{y}=324$....(i)
Now, $\frac{20}{100}\mathit{x}+\frac{25}{100}\mathit{y}=71$
$20\mathit{x}+25\mathit{y}=71\times 100$
$4\mathit{x}+5\mathit{y}=1420$....(ii)
On solving Eqs. (i) and (ii), we get
$4\mathit{x}+5\mathit{y}=1420$
$4\mathit{x}+4\mathit{y}=1296$
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   $\mathit{y}=124$
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$\therefore$ There are 124,25 paisa coins