Answer:
5605.01 dollars
Step-by-step explanation:
Given that after 3 years your brother will pay your 7100 dollars.
If invested otherwise, interest is 8.20 percent per year
Let P be the amount invested
Then after 3 years at compound interest final amount
A =[tex]P(1+\frac{8.2}{100})^3\\ =P(1.082)^3[/tex]
This must be less than or equal to 7100 if willing to lend to brother
i.e. [tex]P(1.082)^3 \leq 7100\\P\leq 5605.01[/tex]
So willing to lend upto 5605.01 dollars