The convoy transported a batch of materials to the disaster area at a speed of 60km/hour and arrived in the disaster area in 9 hours. 20% faster on the way back, so how many hours will it take less to return than to go?
车队向灾区运送一批物资，去时60km/小时，9小时到达灾区．回来时速度提高20%这样返回时比去时少用多少小时？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">60 * (6/5)</gadget>
<output>72</output>

<gadget id="calculator">9 / 72</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">60 * (1/8)</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">9 - (15/2)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>