Answer with Step-by-step explanation:
We are given that
If you earned upto $113,700 in 2013 from an employer then your security tax=6.2% of income
If you earned over $113,700 then, you paid amount of tax=$7049.40
We have to find the money you would have made when you paid $4000 in social security tax in 2013.
Let x be the income and f(x) be the amount of tax.
![f(x)=\left\{\begin{matrix}0.062x&,if\ \ 0<x\leq113700 \\ 7049.40&,if\ \ 113700<x\end{matrix}\right.](https://img.qammunity.org/2020/formulas/mathematics/high-school/5ym4l0jow2fzp2258i5s7qp6yb3ex3y8k4.png)
Substitute the values then we get
![4000=0.062x](https://img.qammunity.org/2020/formulas/mathematics/high-school/dz7ugajoxl80aoklibzo7gnqf1p6fau28e.png)
$64516.13
When you would have mad $64516.13 then you paid $4000 in social security tax in 2013.