2. A ship can carry fresh water for 20 people to drink for 50 days. Thirty days after the departure, four people left the ship and landed. If everyone drinks the same amount of water every day, who else can drink for a few days?
A group has installed a batch of tape recorders, and 925 sets have been assembled. It will take 40 days to assemble 2 sets more than before, and 5 sets less on the last day. If it is assembled according to the original working efficiency, it will take another 3 days to work. How many tape recorders will this group assemble?
4. Laying the railway, it was originally planned to lay 3.5 kilometers a day and complete it in 42 days. In fact, the daily paving volume is 40% more than originally planned. How many days did it actually take?
5. There is a group of saplings, a group of students has 5 saplings, and there are 6 saplings left. If two of them plant four seedlings, the remaining six seedlings will be planted accurately. How many students are there in this group? How many trees have been planted?
6. Prepare new coatings with coating A with a value of 100 yuan and coating B with a value of 240 yuan. The new coating has less 3 yuan per kilogram than coating A and more 1 yuan than coating B. How much is this new coating per kilogram?