Two people, A and B, start from A to B at the same time. After 3 hours, A arrives at B first, and B will reach B in 1 hour. At this time, A and B have traveled a total of 35 kilometers. Find the distance between AB and AB.
甲、乙两人同时从A地出发到B地，经过3小时，甲先到B地，乙还要1小时到达B地，此时甲、乙共行了35千米．求AB两地的路程．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">35 / 7</gadget>
<output>5</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>