Answer:
![4800+183x\geq 8000](https://img.qammunity.org/2020/formulas/mathematics/college/du495yb4heti8ue4d5si3ygyvmc11nc6an.png)
She must sell at least 18 policies to make an annual income of at least $8,000
Explanation:
Let
be the number of policies Mrs. Robinson must sell
We know that Mrs. Robins makes 3% on commission for each policy sold. We also know that the average price of a policy is $6,100, so she makes 3% of $6,100 per policy sold. To find the 3% of $6,100 we just need to multiply 3% and $6,100; then dive the result by 100%:
![(3*6,100)/(100) =183](https://img.qammunity.org/2020/formulas/mathematics/college/dq3o6bthfbky1mw6taiucll6ppen5q1cb0.png)
Now we know that she makes $183 per policy sold. Since
is the number of policies sold,
is her total commission for selling
policies.
We also know that She makes $4,800 per year, so her total annual income is her salary plus her commissions, in other words:
![4800+183x](https://img.qammunity.org/2020/formulas/mathematics/college/6b7ap5uokrzz7iyh7ulj595dl39dnmm87a.png)
Finally, we know that she wants to make at least $8,000, so her salary plus her commissions must be greater or equal than $8,000:
![4800+183x\geq 8000](https://img.qammunity.org/2020/formulas/mathematics/college/du495yb4heti8ue4d5si3ygyvmc11nc6an.png)
Let's solve the inequality:
1. Subtract 4800 from both sides
![4800-4800+183x\geq 8000-4800](https://img.qammunity.org/2020/formulas/mathematics/college/d0geubn6zo642d9fjxmmkpsxihi5xt1v6k.png)
![183x\geq 3200](https://img.qammunity.org/2020/formulas/mathematics/college/u6unhkudcfwqwv1tmfnfd48xcapd8nsi4f.png)
2. Divide both sides by 183
![(183x)/(183) \geq (3200)/(183)](https://img.qammunity.org/2020/formulas/mathematics/college/osr2fvuptz1nhhs4ix1w6xbxopz2gmdrsd.png)
![x\geq 17.48](https://img.qammunity.org/2020/formulas/mathematics/college/gl1u7sxiy5nq9og2xvubi8l5roul9bu1kq.png)
Since she can't sell a fraction of a policy, we must round the result to the next integer:
![x\geq 18](https://img.qammunity.org/2020/formulas/mathematics/college/tuon63rkpqfxynewqqzhxglz4gmvnd7a33.png)
We can conclude that she must sell 18 policies to make an annual income of at least $8,000.