The ratio of roosters to hens in a chicken farm is 3:2. It is known that there are 450 roosters and how many hens are there.
养鸡场的公鸡与母鸡的只数比是3：2，已知公鸡有450只，母鸡有多少只．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">450 * (2/3)</gadget>
<output>300</output>

<result>300</result>