The East and West cities are 75 kilometers apart. Xiaoming walks from east to west at 6.5 kilometers per hour; Xiaoqiang walks from west to east at 6 kilometers per hour; Xiaohui rides a bicycle from east to west at 15 kilometers per hour. The three started at the same time. On the way, Xiaohui met Xiaoqiang and turned back to ride eastward, met Xiaoming and turned back to ride westward, met Xiaoqiang again and turned back to ride eastward, and so on, until the three met on the way. May I ask: How many kilometers did Xiaohui ride in total?
东、西两城相距75千米．小明从东向西走，每小时走6.5千米；小强从西向东走，每小时走6千米；小辉骑自行车从东向西走，每小时行15千米．三人同时动身，途中小辉遇见小强即折回向东骑，遇见了小明又折回向西骑，再遇见小强又折回向东骑，…这样往返，直到三人在途中相遇为止．请问：小辉共骑了多少千米？
<gadget id="calculator">6.5 + 6</gadget>
<output>12.5</output>

<gadget id="calculator">75 / 12.5</gadget>
<output>6</output>

<gadget id="calculator">6 * 15</gadget>
<output>90</output>

<result>90</result>