<h2>
Answer:</h2>
The graph which represents Jack and Jill's number of pails over time is:
-     graph of line going through (1,7) and (3,11) 
<h2>
Step-by-step explanation:</h2>
It is given that:
Jack and Jill had 5 pails of water. Each trip up the hill, Jack and Jill obtained 2 more buckets of water. 
Let x be the number of hills they tripped.
and y denote the number of buckets of water they have.
Then the equation which represent the relationship between y and x is:
              
On making  a table for x and y:
         x             y
         1              7
         2             9
         3             11
         4             13
         5             15
         6             17
 Hence, the graph will pass through the points (1,7) (2,9) (3,11) (4,13) (5,15) (6,17) and many more.