There are 12 tons of cement, gravel, and sand on the construction site, and they are mixed according to the ratio of 2:5:3 to prepare a concrete. If the gravel is just used up, how many tons of cement are left?
建筑工地上有水泥、石子、沙子各12吨，按2：5：3的比例混合配制一种混凝土，如果石子正好用完，水泥还剩多少吨？
<gadget id="calculator">12 / 5</gadget>
<output>12/5 = around 2.4</output>

<gadget id="calculator">(12/5) * 2</gadget>
<output>24/5 = around 4.8</output>

<gadget id="calculator">12 - (24/5)</gadget>
<output>36/5 = around 7.2</output>

<result>36/5 = around 7.2</result>