If the selling price of 18 oranges is equal to the cost price of 16 oranges,

Let the cost price of one orange be Rs. C, and its selling price be Rs. S

Therefore, $16 \mathrm{C}=18 \mathrm{~S}$

$\mathrm{C}=\frac{18}{16} \mathrm{~S}$

As cost price is more than the selling price,

S. P. $=\left(\frac{100-\text { loss } \%}{100}\right)$ C. P

$\mathrm{S}=\left(\frac{100-\text { loss } \%}{100}\right) \mathrm{C}$

$\frac{\mathrm{S}}{\mathrm{C}}=\left(\frac{100-\text { loss } \%}{100}\right)$

$\frac{16}{18}=\left(\frac{100-\text { loss } \%}{100}\right)$

$\frac{1600}{18}=100-$ loss $\%$

$L$ oss $\%=100-\frac{1600}{18}$

$L$ oss $\%=\frac{1800-1600}{18}$

$=\frac{200}{18}=\frac{100}{9}$

$=11 \frac{1}{9}$

Therefore, the loss percent is $11 \frac{1}{9} \%$.