To determine the theoretical probability of Jonquel rolling a number divisible by 3 on a 20-sided object labeled 1 through 20, we need to find the number of favorable outcomes (numbers divisible by 3) and divide it by the total number of possible outcomes (all numbers from 1 to 20).
Favorable outcomes (numbers divisible by 3): 3, 6, 9, 12, 15, 18 (6 numbers)
Total number of possible outcomes: 20 numbers
Therefore, the theoretical probability of Jonquel rolling a number divisible by 3 is:
Probability = Number of favorable outcomes / Total number of possible outcomes
Probability = 6 / 20
Probability = 0.3 or 30%