Question

Is this relationship proportional or not and give at least proof. Time: 1, 2, 3, 4, 5, 10 Pages: 65,130,195,260,325,650 ​

Answer 1

A relationship is proportional if the ratio between the output and the input is constant:

$y=kx \iff \dfrac{y}{x} = k$

In your case, we have

$\dfrac{65}{1} = \dfrac{130}{2} = \dfrac{195}{3} = \dfrac{260}{4} = \dfrac{325}{5} = \dfrac{650}{10} = 65$

This means that it takes the reader one unit of time to read 65 pages. So, after 2 units of time, he reads 130 pages, and so on.