Final answer:
The probability that Daeshon will not be chosen as a guide is about 90.5%, calculated by multiplying the individual probabilities of not being chosen for each of the two guide positions.
Step-by-step explanation:
To calculate the probability that Daeshon will not be picked as a guide out of 21 students when 2 are chosen randomly, first, we find the probability of Daeshon being chosen. Since two students are picked, there are two potential outcomes to consider for Daeshon: being chosen as the first guide, or being chosen as the second.
The probability of not being picked first is 20/21 since there are 20 other students. If Daeshon wasn't picked first, the chance he is not picked as the second guide is now 19/20 (only 20 students are left). The overall probability is found by multiplying these probabilities together:
Probability not picked first x Probability not picked second given not picked first = (20/21) x (19/20) = 380/420 or approximately 0.905 (which can be converted to a percentage as 90.5%). Therefore, there is a 90.5% chance Daeshon will not be picked.