If s varies directly as (r+1),and s=8 when r=3, calculate the value of r when s=20

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?

Give the equations of two different lines that are perpendicular to the line 3x + 4y = 7.

What is always true when two whole numbers are subtracted?