For a tricycle, the diameter of the front wheel is 3dm, and the radius of the rear wheel is 1dm. How many revolutions does the rear wheel take to cover the distance traveled by the front wheel in 50 revolutions?
一辆三轮车，前轮直径是3dm，后轮半径是1dm，前轮转50周所行的路程，后轮要转多少周？
<gadget id="calculator">150 / 2</gadget>
<output>75</output>

<result>75</result>