Ship A departs from port A and travels 18 kilometers per hour. After 4 hours, ship B catches up with ship A in 10 hours after departure. What is the speed of ship B?
甲船从A港出发，每小时行18千米，4小时后，乙船出发10小时追上甲船，乙船的速度是多少．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">18 * (2/5)</gadget>
<output>36/5 = around 7.2</output>

<gadget id="calculator">18 + (36/5)</gadget>
<output>126/5 = around 25.2</output>

<result>126/5 = around 25.2</result>