Generate random and unique probabilities based on the data in a column rstudio

Question

I have a database with different ages (16-85) I'm trying to assign a random probability to each age but following the next conditions:

1. The random probability should be between 20-100
2. The probability should be higher in the lowest and highest values

For example: I have this data frame

Age	Probability
16	85
18	80
25	70
30	50
35	40
65	60
75	65
85	70

I'd really appreciate if you can help me with this.

Tank you so much!