SOLUTION: A box contains 7 red cards, 2 blue cards, 3 green cards. What is the he smallest number of cards we must take from the box to make sure that we have 2 red cards?
A)2
B)4
C)5
D
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A)2
B)4
C)5
D
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Question 1143739: A box contains 7 red cards, 2 blue cards, 3 green cards. What is the he smallest number of cards we must take from the box to make sure that we have 2 red cards?
A)2
B)4
C)5
D)7 Answer by ikleyn(52783) (Show Source):
In the worst case, we should take all blue cards (2) and all green cards (3).
2 + 3 = 5.
After taking the 6-th card we inevitably will have at least one red card,
and after taking the 7-th card we inevitably will have at least two red cards.
ANSWER. After taking 7 (seven) cards we inevitably will have at least two red cards.