Is there a picture of the graphs?
If the pool has 18 married and 22 not married, this means there are 40 people total
this means there’s a 18/40 probability that people who are married will be chosen
18/40 = 2/5
There is a 22/40 probability people who are un married will be chosen
22/40 = 11/20
21 because you can do 84 divided by 21 or you can also do 4 times any number that sounds like it would =84. (Stick with option 1 unless you are super confused)
we can mark points on the graph shown , check the image I have shared with this for the points .
Formula for slope = 
So for Line A points are (1,3) and (0,-1)
So using t he formula slope is = 
slope of line A =4
For Line B the points are (0,4) and (3,-5)
So using t he formula slope is = 
slope of line B = -3