father and son are running a race on a 100-meter track. It is known that the father can run 6 steps when the son runs 5 steps, and the distance that the son runs 7 steps is equal to the distance that the father runs 4 steps. Now the son stands at the midpoint of the 100-meter runway and starts running at the same time. If the father takes 14 seconds to run to the finish line, how many seconds does it take for the son to run to the finish line?
父亲与儿子在100米跑道上进行赛跑，已知儿子跑5步的时间父亲能跑6步，儿子跑7步的距离与父亲跑4步的距离相等．现在儿子站在100米的中点处，站在100米跑道的起点处同时开始跑，如果父亲跑到终点用了14秒，那么儿子跑到终点需要多少秒？
<gadget id="calculator">14 / 2</gadget>
<output>7</output>

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

<gadget id="calculator">7 / 5</gadget>
<output>7/5 = around 1.4</output>

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

<gadget id="calculator">4 / 6</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(7/5) / (2/3)</gadget>
<output>21/10 = around 2.1</output>

<gadget id="calculator">7 * (21/10)</gadget>
<output>147/10 = around 14.7</output>

<result>147/10 = around 14.7</result>