check the picture below.
so we know Bethany's payrate, her slope is 11.75, namely $11.75/hr, for for every hour, she makes 11.75 bucks.
now, let's use those red-circled points, to get Grant's slope, and therefore his payrate,
![\bf (\stackrel{x_1}{3}~,~\stackrel{y_1}{38.70})\qquad (\stackrel{x_2}{7}~,~\stackrel{y_2}{90.30}) \\\\\\ % slope = m slope = m\implies \cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{90.30-38.70}{7-3}\implies \cfrac{51.6}{4}\implies 12.9](https://tex.z-dn.net/?f=%5Cbf%20%28%5Cstackrel%7Bx_1%7D%7B3%7D~%2C~%5Cstackrel%7By_1%7D%7B38.70%7D%29%5Cqquad%20%0A%28%5Cstackrel%7Bx_2%7D%7B7%7D~%2C~%5Cstackrel%7By_2%7D%7B90.30%7D%29%0A%5C%5C%5C%5C%5C%5C%0A%25%20slope%20%20%3D%20m%0Aslope%20%3D%20%20m%5Cimplies%20%0A%5Ccfrac%7B%5Cstackrel%7Brise%7D%7B%20y_2-%20y_1%7D%7D%7B%5Cstackrel%7Brun%7D%7B%20x_2-%20x_1%7D%7D%5Cimplies%20%5Ccfrac%7B90.30-38.70%7D%7B7-3%7D%5Cimplies%20%5Ccfrac%7B51.6%7D%7B4%7D%5Cimplies%2012.9)
low and behold, Grant makes 12.90 or 12.9 bucks every hour.
well, Bethany does 11.75 hmmm what's their difference?
12.90 - 11.75
1.15
so 12.90 is greater than 11.75 by 1.15, meaning, Grant makes 1.15 bucks more every hour than Bethany.