A crew is digging a man-made lake. They started in the morning and then had lunch. After the lunch break, the crew dug down another 1.8 feet before heading home. Before they left, the boss said, "If you dig the amount you dug today every day, then it will take you 3.5 days to finish." The bottom of the lake will have an elevation of 27.3 feet. What was the lake's elevation before the lunch break? We don't know, so let's call it b for break elevation. Which expression represents the elevation of the lake at the end of the first day