I am sorry that I couldn't finish the problem. The best method I can think of for this problem is listing the cases
Try to find all the cases of him buying a toy. The number of those cases will be the denominator of your answer
Then find all the cases of him getting change for the 10 dollar bill before him buying his favorite toy. The number of those cases will be the numerator of your answer.
This might be a little tedious! I hope this helps!
We can easily tell that the new line's y intercept is 1
Therefore, in y=mx+b, we know that b is 1.
So we only need to know the slope.
We put 4x+2y=8 into slope-intercept form, which is y=-2x+4
Parrelel lines have the same slope.
So our new line equation is y=-2x+1
In these problems, ALWAYS know that the slope of two parrelel lines are the same.
Once you have the slope plugged into y=mx+b you can plug in y and x from a given coordinate to find b
THen you can make your equation