Ratio of children, adults and pensioners is 1 : 2 : 8/3 = 3 : 6 : 8.
Let, 3x is number of children.
So, 6x is number of adults and 8x is number of pensioners.
Now,
3x + 6x + 8x = 85
17x = 85
x = 5
Therefore, number of pensioners are 8×5 = 40.
Hence, this is the required solution.