There is a row of 51 telegraph poles, with a distance of 35 meters between poles. Except for the two ends, all the others have been dismantled, and 69 poles have been erected in the middle. What is the average distance between poles and poles?
有一排电线杆共51根，杆与杆之间的距离35米，今除其两端2根之外，其余全部拆除，重在中间竖69根．这时杆与杆之间的平均距离是多少米？
<gadget id="calculator">51 - 1</gadget>
<output>50</output>

<gadget id="calculator">50 * 35</gadget>
<output>1_750</output>

<gadget id="calculator">69 + 1</gadget>
<output>70</output>

<gadget id="calculator">1_750 / 70</gadget>
<output>25</output>

<result>25</result>