How much per cent above the cost price should a shopkeeper mark his goods so that after allowing a discount of 10%

Let $R s 100$ be the cost price.

Gain required = $8 \%$

Therefore, the selling price is $R s 108$.

Let $R s x$ be the marked price.

Then, discount $=10 \%$ of $x$

Selling Price = MP − discount

$\Rightarrow 117=x-\frac{x}{10}$

$\Rightarrow 117=\frac{9 x}{10}$

$\Rightarrow 9 x=1080$

$\Rightarrow x=\frac{1080}{9}$

$\Rightarrow x=120$

$\therefore$ Marked price $=R s 120$

Hence, the marked price is $20 \%$ above the cost price.