Tuesday is 3 less, Wednesday is 4 less, and Thursday is 5 less. For some reason, I can't find the words to describe that pattern but I know that the number of students will probably be 35 on Friday which is a decrease of 6 from Thursday. The pattern can't go on forever because if it keeps decreasing it'll eventually reach negatives and there can't be an attendance of a negative amount of students. Hope that helped, sorry I wasn't very well at explaining the first question but I hope I clarified it a bit. :)