Processing a batch of parts originally planned to be completed by A alone in 10 hours, and by B alone in 15 hours. The two cooperate, and since A makes 5 more parts per hour than the original plan, it is completed 1 hour earlier than the original time. How many parts are there in this batch?
加工一批零件，原计划甲独做要10小时完成，乙独做要15小时完成，两人合作，由于甲每小时比原计划多做5个零件，因此与原定时间提前1小时完成，求这批零件有多少个？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/5) - (1/6)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">5 / (1/30)</gadget>
<output>150</output>

<result>150</result>