Planting a kind of saplings has a survival rate of 90%. In order to ensure that 540 saplings are planted alive, at least how many saplings should be planted.
栽一种树苗，成活率为90%，为保证栽活540棵，至少要栽树苗多少棵．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">540 / (9/10)</gadget>
<output>600</output>

<result>600</result>