A lake near the Arctic Circle i covered by a thick heet of ice during the cold winter month. When pring arrive, the warm air gradually melt the ice, cauing it thickne to decreae at a rate of
0. 2
0. 20, point, 2 meter per week. After
7
77 week, the heet i only
2. 4
2. 42, point, 4 meter thick