Answer
See below
Work Step by Step
Obtain: $f(g(x)=f(0.03x)=0.03x-100000\\g(f(x))=g(x-100000)=0.03(x-100000)=0.03x-3000$
Conclusion: If the sales (x) are greater than $100 000$, then we can get a $3\%$ bonus on sales over $100000$. This also means that the bonus is equal to $3/100(x-100000)$
Composition $g(f(x))$ represents that bonus.