The school bought 200 diaries for the first time, and 150 for the second time. The first time paid 30 yuan more than the second time. How much is each diary?
学校第一次买来200本日记本，第二次买来150本，第一次比第二次多付30元，每本日记本多少元？
<gadget id="calculator">200 - 150</gadget>
<output>50</output>

<gadget id="calculator">30 / 50</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>