we have the following equation
[tex]m(t)=430+430\cdot0.02\cdot t[/tex]where t is the time in years, as we have 9 months, we have to change to years
[tex]t=\frac{9}{12}=\frac{3}{4}=0.75[/tex]so after 9 months we get
[tex]430+430\cdot0.02\cdot0.75=430+6.45[/tex]So she will earn $6.45 in 9 month
