If y varies directly with x, means that they can be modeled by a linear equation, lets choose a line with 0 y intercept, that is: y = mx + b y = mx where m is the slope of the line, now we plug in the data we have: y = mx 20/3 = m(30) solving for m: m = (20/3)(1/30) m = 20/90 m = 2/9 so the line equation, or function modeling the y and x relationship is: y = (2/9)x
