There are 50 more hens than roosters, and the number of hens is three times that of roosters. How many hens are there?
母鸡比公鸡多50只，母鸡的只数是公鸡的3倍．母鸡有多少只．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<gadget id="calculator">25 * 3</gadget>
<output>75</output>

<result>75</result>