Correct Answer: $32 \frac{33}{40}$%

Solution : Let the initial price of the scooter be 100.
After successive increment of 10%, 5%, and 15%, the price becomes
= $100\times\frac{110}{100}\times\frac{105}{100}\times\frac{115}{100}$
= $100\times\frac{11}{10}\times\frac{21}{20}\times\frac{23}{20}$
= $\frac{11\times21\times23}{40}$
= $\frac{5313}{40}$
Difference = Price after increment – initial price = $\frac{5313}{40}-100=\frac{5313-4000}{40}=\frac{1313}{40}$
$\therefore$ Percentage increased
= $\frac{\text{Difference}}{\text{Initial price}}\times 100$
= $\frac{\frac{1313}{40}}{100}\times 100$
= $\frac{1313}{40}$
= $32 \frac{33}{40}$%
Hence, the correct answer is $32 \frac{33}{40}$%.