A boat travels downstream from point A, reaches point B at 35 kilometers per hour, and then goes upstream back to point A. It takes 4 hours more to flow upstream than to flow downstream. Given that the water speed is 5 kilometers per hour, how many kilometers is the distance between A and B?
一条船从A地顺流而下，每小时35千米到达B地后，又逆流而上回到A地．逆流比顺流多用4小时，已知水速是每小时5千米，则A、B两地相距多少千米？
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">35 - 10</gadget>
<output>25</output>

<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 * (2/5)</gadget>
<output>10</output>

<gadget id="calculator">35 * 10</gadget>
<output>350</output>

<result>350</result>