Mindy read 8 pages of her book the first day, 15 pages the second day, and 22 pages the third day. if the pattern continues, how many pages of her book will she read on the sixth day

Entirely impossible to know, there are an infinite number of sequences which have the terms 8, 15, and 22 for n=1,2,3 - you could say that if you wanted to give a "smart" answer and it would be true

otherwise 43 pages on 6th day I think

43 pages 8+7=15 15+7=22 22=7=29 29+7=36 36+7=43