The incubation period of a chicken is 21 days, the incubation period of a chicken is that of a duck (3/4), and the incubation period of a duck is that of a goose (14/15), how many days is the incubation period of a goose?
鸡的孵化期是21天，鸡的孵化期是鸭的(3/4)，鸭的孵化期是鹅的(14/15)，鹅的孵化期是多少天？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">14 / 15</gadget>
<output>14/15 = around 0.933333</output>

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

<result>30</result>