Aman sells two watches at 99 each. On one he get 10% profit and on the other he loses 10%. His net gain or loss percent is

Selling price of both watches = Rs. 99

Cost price of watch on which he get 10% profit = $$C_1=99\times\frac{100}{100+10}$$

= $$99\times\frac{10}{11}=Rs.$$ $$90$$

Similarly, cost price of watch on which he get 10% loss = $$C_2=99\times\frac{100}{100-10}$$

= $$99\times\frac{10}{9}=Rs.$$ $$110$$

=> Total CP = $$(110+90)=Rs.$$ $$200$$

and total SP = $$(99+99)=Rs.$$ $$198$$

$$\therefore$$ Loss % = $$\frac{(200-198)}{200}\times100=1\%$$

=> Ans - (A)