Xiao Ming intends to arrive at school 5 minutes before class, and walks from home to school at a speed of 4 kilometers per hour. When he walks 1 kilometer, he finds that his watch is 10 minutes slow, so he runs forward immediately. He arrives at school just on time for class, and then forgets For a moment, if you start running from home, you can arrive at school 9 minutes earlier than before. What is Xiao Ming's running speed in kilometers per hour?
小明打算上课前5分钟到校，以每小时4千米的速度从家步行去学校，当他走了1千米，发现手表慢10分钟，立即跑步前进，到学校恰好准时上课，后来算了一下，如果从家开始就跑步，可以比原来一直步行早9分钟到学校，小明跑步的速度是每小时多少千米．
<gadget id="calculator">9 - 5</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">4 / 60</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/4) - (1/15)</gadget>
<output>11/60 = around 0.183333</output>

<gadget id="calculator">1 / (11/60)</gadget>
<output>60/11 = around 5.454545</output>

<result>60/11 = around 5.454545</result>