tourist starts at 9:15 a.m. from Qujiang Wharf by boat to enjoy the beautiful scenery on both sides of the Qujiang River. He must return to the wharf no later than 12:00 noon on the same day. It is known that the flow rate of the river is 1.4 km/h, and the speed of the boat in still water is 3 km/h. If tourists rest for 15 minutes every 30 minutes (not docking), they can only return after a certain rest. , then what is the maximum distance he traveled in a boat from the pier in kilometers?
一旅游者于9时15分从渠江一码头乘小艇出发，观赏渠江两岸的优美风景，务必不迟于当日中午12时返回码头．已知河水流速1.4千米/小时，小艇在静水中的速度是3千米/小时，如果旅游者每过30分钟就休息15分钟(不靠岸)，只能在某次休息后才返回，那么他从码头出发乘小艇走过的最大距离是多少千米．
<gadget id="calculator">3 - 1.4</gadget>
<output>1.6</output>

<gadget id="calculator">1.6 * 1.5</gadget>
<output>2.4</output>

<gadget id="calculator">1.4 * 0.5</gadget>
<output>0.7</output>

<gadget id="calculator">2.4 - 0.7</gadget>
<output>1.7</output>

<result>1.7</result>