What is the coefficient of x 36+18x

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?

Can someone me with the property questions for 12 13 and 14 plz

Me n o w. i need t h i s. 10 points