Awuor's annual salary in the 11th year was Kshs. 288,000, and her initial salary was Kshs. 180,000. Determine her annual increment.

a) Given that Awuor's annual salary in the 11th year was Kshs. 288,000, determine:

i) Her annual increment.
We use the formula for compound growth, $A_n = A_0 (1 + \frac{r}{100})^n$, where $A_n$ is the salary in the $n$-th year, $A_0$ is the initial salary, and $r$ is the annual percentage increment.
Given:
Initial salary, $A_0 = \text{Ksh. } 180,000$
Salary in the 11th year, $A