If a coin has an equal probability of landing heads up or tails up each time it is flipped , what is the probability that the coin will land heads up exectly twice in 3 consecutive flips ?
A. 0.125
B. 0.25
C. 0.375
D. 0.5
E. 0.666
OA C
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If a coin has an equal probability of landing heads up or
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BTGmoderatorDC
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P(HHT) = 1/2 * 1/2 * 1/2 = 1/8.BTGmoderatorDC wrote:If a coin has an equal probability of landing heads up or tails up each time it is flipped , what is the probability that the coin will land heads up exectly twice in 3 consecutive flips ?
A. 0.125
B. 0.25
C. 0.375
D. 0.5
E. 0.666
Since T can occur on the 1st, 2nd or 3rd flip, we multiply by 3:
3(1/8) = 3/8 = 0.375
The correct answer is C.
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We need to determine the probability of HHT and its variations:BTGmoderatorDC wrote:If a coin has an equal probability of landing heads up or tails up each time it is flipped , what is the probability that the coin will land heads up exectly twice in 3 consecutive flips ?
A. 0.125
B. 0.25
C. 0.375
D. 0.5
E. 0.666
OA C
Source: GMAT Prep
P(HHT) = (1/2)^3 = 1/8
Since we can arrange HHT in 3!/2! = 3 ways, the overall probability is 3 x 1/8 = 3/8 = 0.375.
Answer: C
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