Two people, A and B, rode camels to explore the desert. They walked 40 kilometers to the depths of the desert every day. It is known that each person can bring food and water for one person at most for 48 days. And water is stored on the way, so that B can take it when he returns. Ask: How many kilometers can B go deep into the desert at most.
A、B两人骑骆驼到沙漠探险，他们每天向沙漠深处走40千米，已知每人最多可以带备一个人48天的食物和水，途中A有事提前返回，如果可以将部分食物和水存放于途中，以备B返回时取用，问：B最多可以深入沙漠多少千米．
<gadget id="calculator">48 / 4</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<gadget id="calculator">24 + 48</gadget>
<output>72</output>

<gadget id="calculator">72 / 2</gadget>
<output>36</output>

<gadget id="calculator">40 * 36</gadget>
<output>1_440</output>

<result>1_440</result>