Ravi purchased an old scooter for $Rs.12000$ and spent $Rs.2850$ on its overhauling. Then he sold it to his friend for $Rs.13860.$ How much percent did he gain or lose?

Cost price $=Rs.12000,$ overhead charges $=Rs.2850$

$\therefore$ Total cost price $=Rs(12000+2850)=Rs.14850$

Selling Price $=Rs.13860$

Selling Price $<$ Cost Price $\to$ Loss

$\therefore$ Loss $=$ Cost price $-$ Selling price

$\Rightarrow$ Loss $=Rs.(14850-13860)=Rs.990$

Loss percent $=\frac{Loss}{CostPrice}\times 100\%$

Loss percent $=\frac{990}{14850}\times 100\%=6.67\%$

So, Ravi incurred a loss of $6.67\%$.