12.From Wittenberg to Göttingen, two students are walking. The first one walked 7 miles daily. The second one walked 1 mile on the first day, 2 miles on the second day, 3 miles on the third day, and so on, walking 1 mile more each day than the previous day. When will the second catch up with the first?
12. On the first day, the second student walked 6 miles less than the first, on the second day 5 miles less, and so on. By the seventh day, the students will walk the same distance. After that, on the eighth day, the second student will walk 1 mile more, on the ninth day 2 miles more, and so on. They will meet at the end of the 13th day.