Afarmer has 60 bakes of hay in his barn . he feeds his cows 4 bakes each day .which graph represent the number of bales in the barn h after feeding his cows for x days

The 3rd graph is the correct choice with the line going from 60 on the y-axis to 15 on the x-axis.   
 Since the farmer started with 60 bales, the y-intercept of the line will be at 60. And since the farmer is feeding 4 bales per day to the cows, the line will have a slope of -4. So every increment of X to the right, the line will go down 4 increments along Y. So let's look at the graphs and see which one does that. At the rate the farmer is feeding the cows, the graph will have a y value of 0 after (60/4 = 15) days. So we have a line intersecting the Y axis at 60 and the X axis at 15.   
 The first graph is immediately eliminated since it starts out at 4 bales. The remaining three graphs are OK on the y-intercept issue.   
 The second graph intersects the X axis at 4 days. So that's wrong.   
 The third graph intersects the X axis at 15 days. So it's the correct answer.   
 The fourth graph can't be completely seen. But given the slope of the line, it looks like it will intersect the X axis at 20 days, so it's wrong too.