You are adding 3 each time.
81, 84, 87, 90, 93, 96, 99
87
86.90909090 recurring or 86 and one eleventh.
84, 87, 90, 93, 96, 99
765
80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100
Nine: 78, 81, 84, 87, 90, 93, 96, 99, 102.
(100+65+93+84+90+96) ÷ 6 = 88 is the average
80, 81, 82, 84, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100.
84, 87, 90, 93, 96, 99, 102, 105, 108.
Here they are ! 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94. 95. 96. And 97 !
around 93 percent.