Create a pattern with the rule n×3+1

Rachel reads 1/5 of the pages of a book plus 12 pages on the first day. on the second day, she reads 1/4 of the remaining pages plus 15 pages. on the third day, she reads 1/3 of the remaining pages plus 18 pages. on the fourth day, she reads the remaining 70 pages. how many total pages are in the book?

Ineed to know the ordered pairs for this equation i need the answer quick because it’s a timed test

Interpret the following expression (5y^2-7)^3/(2y)^2