section of road is divided into three sections: uphill, flat slope, and downhill. The ratio of the length of each section is 1:2:3. The ratio of the speed of each section of a person walking this section is 4:5:6. It is known that his uphill speed is 3 kilometers per hour, and the total length of the uphill road is 5 kilometers. Ask him how many hours it took him to complete the journey.
一段路分为上坡、平坡、下坡三段，各段路程长的比1：2：3，某人走这段路的每段速度比为4：5：6．已知他上坡速度是每小时3千米，上坡路全长的5千米，问此人走完全程用了多少小时．
<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">3 * (5/4)</gadget>
<output>15/4 = around 3.75</output>

<gadget id="calculator">2 / (15/4)</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">5 * (8/15)</gadget>
<output>8/3 = around 2.666667</output>

<gadget id="calculator">6 / 4</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">3 * (3/2)</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">3 / (9/2)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">5 * (2/3)</gadget>
<output>10/3 = around 3.333333</output>

<gadget id="calculator">(5/3) + (8/3) + (10/3)</gadget>
<output>23/3 = around 7.666667</output>

<result>23/3 = around 7.666667</result>