The diesel oil carried by a ship can be used for up to 6 hours. When driving out, the wind is down, and the driving speed is 30 kilometers per hour. When driving back against the wind, the distance traveled per hour is downwind (4/5). How far has the ship sailed before it should turn back?
一艘轮船所带的柴油最多可以用6小时．驶出时顺风，每小时行驶30千米．驶回时逆风，每小时行驶的路程是顺风时的(4/5)．这艘轮船最多驶出多远就应往回驶了？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">30 * (4/5) * 6</gadget>
<output>144</output>

<gadget id="calculator">30 * (4/5)</gadget>
<output>24</output>

<gadget id="calculator">30 + 24</gadget>
<output>54</output>

<gadget id="calculator">144 / 54</gadget>
<output>8/3 = around 2.666667</output>

<gadget id="calculator">30 * (8/3)</gadget>
<output>80</output>

<result>80</result>