The school bought back 75 sets of desks and chairs for the first time, and 100 sets of the same desks and chairs for the second time. The second time spent 4250 yuan more than the first time. How much is each set of desks and chairs?
学校第一次买回75套课桌椅，第二次买回同样的课桌椅100套，第二次比第一次多用4250元．每套课桌椅多少元？
<gadget id="calculator">100 - 75</gadget>
<output>25</output>

<gadget id="calculator">4_250 / 25</gadget>
<output>170</output>

<result>170</result>