The correct equation is y = 9x + 20, where x is equal to the number of hours. 
This is because at 0 hours of work, he still has the 20 handed out. This gives us the point of (0, 20). 
At one hour we know he has handed out 9 more, giving us the point of (1, 29). 
We can then use the slope formula to find the slope of the equation. 
m = (y1 - y2)/(x1- x2)
m = (29-20)/(1-0) 
m = 9/1 
m = 9. 
Then you can use 20 as the y intercept because the y intercept is when the x value equals 0. Use them in slope intercept form and you have y = 9x + 20.