Uncle Wang brought 900 yuan to buy fertilizer. I bought 15 bags of fertilizer, and there is 30 yuan left. How much is the price per bag of fertilizer?
王大爷带了900元去买化肥．买了15袋化肥，还剩30元．每袋化肥的价格是多少钱？
<gadget id="calculator">900 - 30</gadget>
<output>870</output>

<gadget id="calculator">870 / 15</gadget>
<output>58</output>

<result>58</result>