A person first increases the price of a commodity by 10% and then he announces a discount of 15%. The actual discount on the original price is -

Let the original price of the commodity be Rs. 100.
Increased price = Rs. 110
Price after discount
$$\eqalign{ & = {\text{85}}\% {\text{ of Rs}}{\text{.110}} \cr & {\text{ = Rs}}{\text{.}}\left( {\frac{{85}}{{100}} \times 110} \right) \cr & = {\text{Rs}}{\text{. 93}}{\text{.50}}{\text{}} \cr} $$
∴ Discount on original price = (100 - 93.50)% = 6.5%