To process a batch of parts, A and B cooperate to complete it in 3 hours, and A alone completes it in 5 hours. It is known that A processes 6 more parts per hour than B, how many parts are there in this batch?
加工一批零件，甲乙合作3小时完成，甲独做5小时完成．已知甲每小时比乙多加工6个零件，这批零件共有多少个？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) - (1/5)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">(1/5) - (2/15)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">6 / (1/15)</gadget>
<output>90</output>

<result>90</result>