The incubation period of goose is 30 days, the incubation period of duck is that of goose (14/15), and the incubation period of chicken is that of duck (3/4). How many days does it take for a chicken to hatch?
鹅的孵化期是30天，鸭的孵化期是鹅的(14/15)，鸡的孵化期是鸭的(3/4)．鸡的孵化期是多少天？
<gadget id="calculator">14 / 15</gadget>
<output>14/15 = around 0.933333</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">30 * (14/15) * (3/4)</gadget>
<output>21</output>

<result>21</result>