The diameter of the front wheels of a tractor is 0.8m, and the diameter of the rear wheels is 1m. After driving for a certain distance, the front wheels turn 50 times, how many times does the rear wheel turn?
一台拖拉机的前轮直径是0.8m，后轮直径是1m，行驶一段路程后，前轮转了50圈，后轮转了多少圈？
<gadget id="calculator">0.8 * 3.14 * 50</gadget>
<output>125.6</output>

<gadget id="calculator">125.6 / 3.14</gadget>
<output>40</output>

<result>40</result>