Father and son set off from east and west places facing each other at the same time, and the distance between the two places is 10 kilometers. The father walks 6 kilometers per hour, and the son walks 4 kilometers per hour. The father brought a puppy, and the puppy ran towards the son at a speed of 10 kilometers per hour. When it met the son or the father, it turned back immediately, and did not stop until the father and the son met. So how many kilometers did the puppy run in total?
爸爸和儿子从东西两地同时相对出发，两地相距10千米．爸爸每小时走6千米，儿子每小时走4千米．爸爸带了一只小狗，小狗用每小时10千米的速度向儿子跑去，遇到儿子或爸爸立即折返，直到爸爸和儿子相遇才停．那么小狗一共跑了多少千米的路程．
<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">10 / 10</gadget>
<output>1</output>

<gadget id="calculator">10 * 1</gadget>
<output>10</output>

<result>10</result>