A dealer marks his goods at 35% above the cost price and allows a discount of 20% on the marked price.

Solution:

Let Rs 100 be the CP.

Then, marked price $=R s 135$

Discount $=20 \%$ of $\mathrm{MP}$

$=\frac{20}{100} \times 135$

$=27$

Selling price = marked price − discount

= 135 − 27

= Rs 108

Now, gain = SP − CP

=108 − 100

=Rs 8

$\therefore$ Gain percentage $=\frac{\text { gain }}{\mathrm{CP}} \times 100$

$=\frac{8}{100} \times 100$

$=8 \%$