A percent change implies multiplication by a growth factor.
Set up the situation as an algebra problem.
1. What do you multiply by to get from $2{,}000$ to $10{,}000\text{?}$
$2{,}000 \cdot b = 10{,}000$
What is the growth factor b?
$b =$
2. What percent increase does this represent?
$\%$