The wear of the front and rear wheels of the bicycle is different. There is a bicycle with new front and rear wheels that can be interchanged. The tires can travel 5,000 kilometers on the front wheels and 3,000 kilometers on the rear wheels. Using these two new tires, how many kilometers can the bicycle travel at most?
自行车前后轮磨损度不相同．有一辆自行车，车轮的前后轮都是崭新的，可以互相交换．轮胎在前轮位置可以行5000千米，在后轮位置可以行驶3000千米，使用这两个新轮胎，这辆自行车最多可以行驶多少千米．
<result>3_750</result>