The distance between A and B is 56 kilometers. It takes 1.4 hours to travel by car and 14 hours to walk. A person starts from a place, walks for 3.5 hours and then changes to a car. How many hours did it take him to reach B?
甲、乙两地相距56千米，汽车行完全程需1.4小时，步行要14小时．一个人由甲地出发，步行3.5小时后改乘汽车．他到达乙地总共用几小时？
<gadget id="calculator">56 / 14</gadget>
<output>4</output>

<gadget id="calculator">4 * 3.5</gadget>
<output>14</output>

<gadget id="calculator">56 - 14</gadget>
<output>42</output>

<gadget id="calculator">56 / 1.4</gadget>
<output>40</output>

<gadget id="calculator">42 / 40</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">(21/20) + 3.5</gadget>
<output>4.55</output>

<result>4.55</result>