The orchard transported 180 peach seedlings and planted 45 in 5 hours. According to this calculation, how many hours will it take to plant these saplings?
果园运进180棵桃树苗，用了5小时种了45棵．照这样计算，栽完这些树苗，共需要多少小时？
<gadget id="calculator">45 / 5</gadget>
<output>9</output>

<gadget id="calculator">180 / 9</gadget>
<output>20</output>

<result>20</result>