A boy buys 9 apples for Rs 9.60 and sells them at 11 for Rs 12.

C.P of 9 apples $=$ Rs $9.60$

$\therefore$ C.P of 1 apple $=$ Rs $\frac{9.60}{9}=$ Rs $\frac{16}{15}$

S.P of 11 apples $=$ Rs 12

$\therefore$ S.P of 1 apple $=$ Rs $\frac{12}{11}$

Clearly, S.P of 1 apple $>$ C.P of 1 apple

So, we get profit on selling apples

Gain $\%=\left(\frac{\operatorname{gain} \times 100}{\text { C.P. }}\right)$

$=\left(\frac{\frac{12}{11}-\frac{16}{15}}{\frac{16}{15}}\right) \times 100$

$=\left(\frac{12 \times 15-16 \times 11}{15 \times 11}\right) \times \frac{15}{16} \times 100$

$=\left(\frac{180-176}{11 \times 16}\right) \times 100$

$=\left(\frac{4}{11 \times 16}\right) \times 100$

$=2 \frac{3}{11} \%$