speedboat sails from Port A to Port C via Port B, traveling 35 kilometers per hour. At the same time, a steamship sails from Port B to Port C. After 5 hours, the two ships arrive at Port C at the same time. It is known that the distance between A and B ports is 30 kilometers. Question: How many kilometers per hour does the ship travel on average?
一艘快艇从甲港经乙港开往丙港，每小时行35千米，同时一艘轮船从乙港开往丙港，5小时后两船同时到达丙港．已知甲、乙两港相距30千米．问：轮船平均每时行多少千米？
<gadget id="calculator">30 / 5</gadget>
<output>6</output>

<gadget id="calculator">35 - 6</gadget>
<output>29</output>

<result>29</result>