If a certain coin is flipped, the probability that the coin will land heads is 1/2. If the coin is flipped 5 times, what is the probability that it will land heads up on the first 3 flips and not on the last 2 flips?
A. 3/5
B. 1/2
C. 1/5
D. 1/8
E. 1/32
coin flipped?
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Hano, for the first three toss, we have to get head. So probability becomes = 1/8. But for the last two toss, we have to get tail. For the last two toss, the probability will be = 1/4. So the total probability will be = 1/8 * 1/4 = 1/32. Get me, Hano?
Correct me If I am wrong
Regards,
Amitava
Regards,
Amitava
- jayhawk2001
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I get 1/32 as well
We are asked to find probability of HHHTT from the 32 possible
combinations. So, 1/32
We are asked to find probability of HHHTT from the 32 possible
combinations. So, 1/32
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- Brent@GMATPrepNow
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We want P(heads on 1st AND heads on 2nd AND heads on 3rd AND tails on 4th AND tails on 5th)
= P(heads on 1st) x P(heads on 2nd) x P(heads on 3rd) x P(tails on 4th) x P(tails on 5th)
= 1/2 x 1/2 x 1/2 x 1/2 x 1/2
= 1/32
Answer: E
Cheers,
Brent