Xiao Ding Ding and Xiao Pang are practicing race walking on a circular track with a circumference of 400 meters. It is known that Fatty walks 60 meters per minute on average, Ding Ding walks 75 meters per minute, and Ding Ding is 100 meters in front of Pang, how many minutes can Ding Ding catch up with Pang?
小丁丁和小胖在周长400米的环形跑道上练习竞走．已知小胖平均每分钟走60米，小丁丁每分钟走75米，小丁丁在小胖前面100米处，多少分钟后小丁丁可以追上小胖？
<gadget id="calculator">75 - 60</gadget>
<output>15</output>

<gadget id="calculator">100 / 15</gadget>
<output>20/3 = around 6.666667</output>

<result>20/3 = around 6.666667</result>