Plz help I’ll mark branlyist

in minutes, since she began filling the trough. The graph shows this relationship
Water Trough Level
у
35
30
y = 3.5x
25
(8, 28)
(6, 21)
Water level (cm)
20
15
10
(0,0)
+
+
5
(1, 3.5)
++
+X
0
1 2 3 4 5 6 7 8 9 10
Time (min)
(a) What rate does the point (8, 28) represent? (3 pts)
28