KhayatiK
Am i missing some crucial knowledge / piece of information here?! my approach was simply to subtract the minimum (smallest number possible (1)) number from each of the colored jellybeans since you can not get minimum than that. so red jelly beans (8-1 =7) +green (4-1=3)+blue (4-1=3) = 7+3+3 =13. but im looking at all the responses and they seem to be taking 1st 12 draws ; worse case scenario etc to approach the question.
Your method isn’t clear and doesn’t hold with other numbers.
For example, if a bag has 12 red, 9 green, and 5 blue marbles, your subtraction method gives 23.
Using the correct worst-case approach: you could draw all 12 red and all 9 green (21 marbles) and still not have a blue one. The next draw, the 22nd, must be blue, so the correct answer is 22.
This shows your shortcut fails. Study the worst-case method shown above and review the similar linked questions for more clarity and practice.