SVP
Joined: 27 Feb 2017
Posts: 1512
Location: United States (WA)
GMAT 1: 760 Q50 V42 
GMAT 2: 760 Q50 V42 
Re: A box contains 5 chips, numbered 1, 2, 3, 4, and 5. Chips are drawn
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26 May 2022, 04:07
In order to have to draw 3 times before the sum of the value exceeds 4.
The first draw cannot be 5, as it will end the sequence.
The first draw cannot be 4, as the sequence will end after the second draw.
The first draw can be 3, then the second draw must be 1, (and the third draw can be anything).
Probability for this sequence is 1/5 * 1/4 * 3/3 = 1/20
The first draw can be 2, then the second draw must be 1, (and the third draw can be anything).
Probability for this sequence is 1/5 * 1/4 * 3/3 = 1/20
The first draw can be 1, then the second draw must be either 2 or 3, (and the third draw can be anything).
Probability for this sequence is 1/5 * 2/4 * 3/3 = 2/20
Altogether, the probability is 1/20 + 1/20 + 2/20 = 4/20 = 1/5
The answer is thus (D).