It takes 15 minutes to saw a piece of wood into 4 sections. According to this calculation, how many minutes will it take to saw it into 8 sections?
一根木料锯成4段需要15分钟，照这样计算，锯成8段一共需要多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

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

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">5 * 7</gadget>
<output>35</output>

<result>35</result>