The probability that at most two jelly beans will be green is approximately 0.854, or 85.4%.
This problem involves a binomial distribution, where each jelly bean can be either green or not green. The probability of success (choosing a green jelly bean) is p = 1/8, and the probability of failure (not choosing a green jelly bean) is q = 1 - p = 7/8.
The probability mass function for a binomial distribution is given by:

where n is the number of trials, k is the number of successes, p is the probability of success, and q is the probability of failure.
In this case, n=11 (Sally chooses 11 jelly beans), and we want to find the probability that at most two will be green jelly beans. This means we need to calculate P(X ≤ 2), which is the sum of the probabilities for k=0,1, and 2.

Let's calculate each term:

Then, add these probabilities to find P(X≤2).
Calculating:


Now, sum these probabilities:

So, the required answer is 0.854.