Jenny's property tax rate is 2%. Her house is currently worth $400,000. The city is about to build a new high-speed rail project nearby, which will increase her house's value by 25%. Jenny can only afford to spend $15,000/year on property tax. How many dollars worth of improvements can she make to her house before her property tax bill gets too high?
Please reason step by step, and put your final answer within \boxed{}.
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