Let the front wheel wear K 1 per kilometer and the rear wheel wear K2 per kilometer. When the wear reaches y, the tire is scrapped.

So there is: 3000× k1= Y2000× K2 = Y.

Change tires after driving x kilometers, and scrap tires after driving z kilometers:

So there are: xk1+zk2 = ykk2+ZK1= y.

Combining the above four equations, it is concluded that X+Z is 4500 kilometers.

So bicycles can travel as far as 4500 kilometers.