Answer:
-0.571428571, or -0.6 if you round it to the nearest tenth
Step-by-step explanation:
Okay, so to break it down, you want to find the difference between each of the numbers right next to each other.
90 -> 91 = 1
91 -> 88 = -3
88 -> 84 = -4
84 -> 86 = 2
86 -> 85 = -1
85 -> 86 = 1
Add up all the differences.
1 - 3 - 4 + 2 -1 + 1 = -4
How many numbers were there? 7
Divide the sum (-4) by 7.
-4/7 = -0.571428571
