Plant a batch of apple trees, the survival rate is 95%, in order to ensure the survival of 380, at least how many apple trees should be planted.
栽一批苹果树，成活率是95%，为了保证成活380棵，至少要栽多少棵苹果树．
<gadget id="calculator">95 / 100</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">380 / (19/20)</gadget>
<output>400</output>

<result>400</result>