Help with maths q

[Taz786]

Can somebody explain the answer to this for me
Please.

There are 15 yellow balls, 10 blue balls and 8 green balls mixed up in a bag.

Paul takes the balls from the bag one by one at random.

He wants to take out at least 2 balls of each colour.
What is the least number of balls that Paul needs to take from the bag to guarantee doing this?

[StainlessSteelCat]

27.

Worst case scenario is he takes all 15 yellow, then all 10 blue, and finally 2 green. Chances are he'd need to take out fewer than 27, but that doesn't guarantee 2 of each colour

[Lougle]

I'm thinking it might be 27.

That would mean worst case scenario, he could pick 15 yellows, 10 blue and the remaining 2 would have to be green.

[Taz786]

Thank you! This was an 11+ question for my daughter. I know the answer now but wow they are quite tricky