Suning Appliance has a batch of computers, sold 30 units in the first week, and sold 25% of the total number in the second week. At this time, the ratio of the number of units sold to the number of remaining units is 2:1. How many computers are there in this batch?
苏宁电器有一批电脑，第一周卖出30台，第二周卖出总数的25%，这时已卖的台数与剩下的台数比是2：1．这批电脑有多少台？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(2/3) - (1/4)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">30 / (5/12)</gadget>
<output>72</output>

<result>72</result>