Xiao Pang and Xiao Ding Ding set off from school to visit the Science and Technology Museum. Fatty walked 80 meters per minute, and Ding Ding walked 100 meters per minute. Pang started first, and Ding Ding started after walking for 5 minutes. As a result, they both arrived at the Science and Technology Museum at the same time. At this time, how many minutes did Ding Ding leave?
小胖和小丁丁从学校出发到科技馆参观．小胖每分钟走80米，小丁丁每分钟走100米，小胖先出发，走了5分钟后小丁丁才出发，结果两人同时到达科技馆．这时小丁丁走了几分钟？
<gadget id="calculator">100 - 80</gadget>
<output>20</output>

<gadget id="calculator">5 / 20</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">80 * (1/4)</gadget>
<output>20</output>

<result>20</result>