The hunting dog chases the hare 30 meters ahead. The hunting dog has big steps, it takes 4 steps for the rabbit to run 7 steps, but the rabbit moves fast, the rabbit can run 4 steps for the hunting dog to run 3 steps. How far can the hound run at least before the hare can be overtaken?
猎狗追赶前方30米处的野兔．猎狗步子大，它跑4步的路程兔子要跑7步，但是兔子动作快，猎狗跑3步时间兔子能跑4步．猎狗至少跑出多远才能追上野兔？
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">7 / 16</gadget>
<output>7/16 = around 0.4375</output>

<gadget id="calculator">3 * (7/16) * 30</gadget>
<output>315/8 = around 39.375</output>

<gadget id="calculator">3 * (7/16)</gadget>
<output>21/16 = around 1.3125</output>

<gadget id="calculator">(21/16) - 1</gadget>
<output>5/16 = around 0.3125</output>

<gadget id="calculator">(315/8) / (5/16)</gadget>
<output>126</output>

<result>126</result>