It takes 9 minutes to saw a piece of cylindrical wood into 4 sections. According to this calculation, how many minutes will it take to saw it into 6 sections?
一根木圆柱形木料，锯成4段，需要9分钟，照这样计算，锯成6段，需要多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>