Two ships, A and B, depart from two ports opposite each other. Ship A travels 30 kilometers per hour, and ship B travels 35 kilometers per hour. One hour after the B boat leaves, the A boat leaves, and after another 4 hours, the two boats meet. How many kilometers are the two ports?
甲、乙两船从两个港口对开，甲船每行小时行30千米，乙船每小时35千米．乙船开出1小时后，甲船才开出，再经过4小时两船相遇．两个港口相距多少千米？
<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">35 * 5</gadget>
<output>175</output>

<gadget id="calculator">120 + 175</gadget>
<output>295</output>

<result>295</result>