If it takes 9 minutes to saw a piece of wood into 3 sections, how many minutes will it take to saw this piece of wood into 5 sections at the same speed?
如果把一根木料锯成3段要9分钟，那么用同样的速度把这根木料锯成5段，要用多少分钟．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">(9/2) * 4</gadget>
<output>18</output>

<result>18</result>