There are 30 coins of 2 cents and 5 cents in Xiaoling's piggy bank, totaling RMB 90.3 cents. How many 2 cent coins are there?
小玲的储蓄罐里有2分和5分的硬币共30个，总计人民币9角3分．其中2分硬币有多少个．
<gadget id="calculator">30 * 5</gadget>
<output>150</output>

<gadget id="calculator">150 - 93</gadget>
<output>57</output>

<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">57 / 3</gadget>
<output>19</output>

<result>19</result>