After Xiaoqiang joined the school's sports training team, his time to run 100 meters was shortened from 18 seconds to 15 seconds. How much faster did Xiaoqiang run 100 meters? (Reserve one decimal place before the percent sign)
小强参加学校体育集训队后，跑100米的时间从原来的18秒缩短到15秒，小强跑百米的速度比原来提高了百分之几？(百分号前保留一位小数)
<gadget id="calculator">100 / 15</gadget>
<output>20/3 = around 6.666667</output>

<gadget id="calculator">100 / 18</gadget>
<output>50/9 = around 5.555556</output>

<gadget id="calculator">(20/3) - (50/9)</gadget>
<output>10/9 = around 1.111111</output>

<gadget id="calculator">(10/9) / (50/9)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>