The engineer arrives at a certain station at the same time every day, and then takes the car that the factory regularly picks up to arrive at the factory on time. One day, the engineer arrived at a certain station 55 minutes earlier, and walked to the factory because the car had not arrived. He met the car that came to pick him up on the road and arrived at the factory 10 minutes earlier than usual. It is known that the car travels 50 kilometers per hour, how many kilometers per hour does the engineer travel on foot?
工程师每天在同一时刻到达某站，然后乘上工厂定时来接的汽车按时到工厂．有一天工程师提前55分钟到某站，因汽车未到就步行向工厂走去，在路上遇见来接他的汽车后乘车比平时提前10分钟到达工厂．已知汽车每小时行50千米，工程师步行每小时行多少千米？
<gadget id="calculator">55 - 5</gadget>
<output>50</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(1/12) / (5/6)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">50 * (1/10)</gadget>
<output>5</output>

<result>5</result>