SSC CHSL 16 Apr 2021 Shift 2 Paper

Let the number of notebooks taken $\mathit{x}$ each.
$\therefore$ Total cost price of $2\mathit{x}$ note books
$=\frac{222}{12}\times \mathit{x}+\frac{225}{10}\times \mathit{x}=41\mathit{x}$
Cost price of 1 note book
$=\frac{41\mathit{x}}{2\mathit{x}}=\mathit{₹}\frac{41}{2}$
$\therefore$ Selling price of 1 note book
$=\frac{41}{2}\times \frac{120}{100}=\mathit{₹}\frac{123}{5}$
$\therefore$ Selling price of 15 note books
$=\frac{123}{5}\times 15=\mathit{₹}369$