If R varies directly as S and inversely as T if R = 8 when S =4 and T=3 then R is equal to

Can someone me and do the problem plz so i can understand it more better

Suppose you are an avid reader and are looking to save money on the cost of books instead of paying about $20 for each book, you decide to look into purchasing a kindle for $120 you can purchase e-books for about $5 each 1. find the slope-intercept equation for the cost of the hard copy of books using x to represent the number of books 2. find the slope-intercept equation for the cost of the kindle with cost of e-books using x to represent the number of books

The amount of data left on the cell phone six gb for 81.5 gb of data is used how much data is available at the beginning of the cycle