Solution: If the number of rented vehicles is X, the rental price of vehicles is 2000+100 (50-x) =100 (70-x), and the maintenance cost is 100x.

∴ profit function f(x)= number of taxis × rental price-maintenance cost spent =100x (70-x)-100x =100x (69-x).

Derive x from f(x) so that f'(x)=0, ∴f'(x)= 100(69-2x)=0. When ∴x=34.5, f(x) reaches the maximum. In addition, x must be an integer, and when the nearest integer value of x=34 or x=35 is taken, f(x) has the maximum value.

When x=34, f(34)=3400*35=f(35). However, considering the cost of vehicle loss, the profit is the largest when renting 34 vehicles, and its value is 1 19000 yuan.

For reference.