We have been given that Sterre charges $35 to file tax returns, but files for free if she only needs the easiest form. Also, she donates $2 to clean water projects per tax return she files.
Further we know that Sterre charged $7,245 and made a donation of $1,242 this year for the tax returns she filed.
Let x be the number of free income tax returns and y be the number of $35 income tax returns.
Therefore, we can set up:
[tex]0x+35y=7245\Rightarrow 35y=7245\Rightarrow y=\frac{7245}{35}=207[/tex]
Since she donates $2 for each return that she files, therefore, we can set up:
[tex]2(x+y)=1242\Rightarrow x+y=621\Rightarrow x+207=621\Rightarrow x=414[/tex]
Therefore,
Sterre filed 414 tax returns for free and filed 207 tax returns for $35
