sv2023
Bunuel why wouldnt we have 8+6+3 as the ans? The person can also pick all red balls continuously and then all blacks and then the last three of green?
We need the
minimum number of marbles to
guarantee that we have at least three marbles of the same color.
So, 8 + 6 + 3 = 17 cannot be an answer because we can guarantee the desired outcome in 7 (17 is not minimum).
You cannot
guarantee the desired outcome in less than 7 picks because as I said in the solution above we can have a case when we pick 2 marbles of each color, so 6 marbles, and we still won't have 3 marbles of the same color.
But for 7 draws, there does not exist a case when after the 7th draw we don't have at least three marbles of the same color. That's why 7 is an answer.
Check other
Worst Case Scenario Questions from our
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Hope it helps.