Correct Answer: INR 10

Solution : The shopkeeper was offering two successive discounts of 20% and 15% on an item whose marked price is INR 1,000
Another shopkeeper was offering a flat 33% discount on the same item
Successive Discount = $x$ + $y$ – $\frac{\text{$x$$y$}}{100}$
The single discount will be = $x$ + $y$ – $\frac{\text{$x$$y$}}{100}$ = 20 + 15 – $\frac{20\times 15}{100}$ = 35 – $\frac{300}{100}$ = 35 – 3 = 32
The single discount will be 32%
Discount = Marked Price $\times \frac{\text{discount}}{100}$ = 1000 $\times \frac{32}{100}$ = INR 320
On offering the discount of 33%.
Discount = Marked Price $\times \frac{\text{discount}}{100}$ = 1000 $\times \frac{33}{100}$ = INR 330
Hence, The positive difference in the nominal amounts of discounts given by the two shopkeepers on the sale of the item will be
= INR 330 - INR 320
= INR 10
Hence the correct answer is INR 10.