Find the single discount equivalent to two successive discounts of

Let the marked price be Rs 100 .

Then, first discount on it $=$ Rs 20

Price after the first discount $=\mathrm{Rs}(100-20)$

= Rs 80

Second discount on it $=10 \%$ of Rs 80

$=\operatorname{Rs}\left(80 \times \frac{10}{100}\right)$

$=\operatorname{Rs} 8$

Price after the second discount $=$ Rs. $(80-8)$

= Rs72

Net selling price $=$ Rs. 72

Single discount equivalent to given successive discounts $=(100-72) \%$

= 28 %

$\therefore$ The single discount equivalent to given successive discounts is $28 \%$.