What is the probability of flipping a fair coin three times and the co

Question

What is the probability of flipping a fair coin three times and the coin landing on heads on exactly two flips?

A. 3/8
B. 5/8
C. 7/8
D. 1/8
E. 1/4

Bunuel · Answer

P(H=2)=\frac{3!}{2!}*\frac{1}{2^3}=\frac{3}{8} , multiplying by 3!/2! as the case of 2 heads out of 3 tries can occur in 3 ways: HHT, HTH, THH - # of permutation of 3 letters out of which 2 are identical.

Answer: A.

vraptor · Answer

Probability = (Favorable combination)/(Total combination)

Favorable combination = (HHT, HTH, THH) ==> 3

Total combination = 8 (2^3)

Probability = (3)/(8)

(A)

JeffTargetTestPrep · Answer

We can assume the first 2 flips are heads (H) and the last flip is tails (T). Thus:

P(H-H-T) = 1/2 x 1/2 x 1/2 = 1/8

However, we need to determine in how many ways we can get 2 heads and 1 tails. That number will be equivalent to how many ways we can organize the letters H-H-T.

We use the indistinguishable permutations formula to determine the number of ways to arrange H-H-T: 3!/2! = 3 ways. (Note: The 3 ways are H-H-T, H-T-H, and T-H-H.)

Each of these 3 ways has the same probability of occurring. Thus, the total probability is:

1/8 x 3 = 3/8

Answer: A

EMPOWERgmatRichC · Answer

Hi All,

This question can be solved simply by listing out the possibilities and answering the exact question that is asked.

Since we're flipping a coin 3 times, there are only (2)(2)(2) = 8 possible outcomes. They are...

HHH
HHT
HTH
THH

TTT
TTH
THT
HTT

We're asked for the probability of getting exactly 2 HEADS from those 3 tosses. There are three ways (out of 8 total) to get exactly 2 heads (HHT, HTH and THH).

Final Answer:  A

GMAT assassins aren't born, they're made,
Rich

monk123 · Answer

What is the probability of flipping a fair coin three times and the coin landing on heads on exactly two flips?

A. 3/8
B. 5/8
C. 7/8
D. 1/8
E. 1/4

probability of flipping a coin 3 times-
3!/2! = 3

getting head on exactly two flips
1- HT - 1/2
2- HT - 1/2
3- TH - 1/2
----------------
= 1/8

PROBABILITY = 3*1/8
 = 3/8

ANSWER (A)

BrushMyQuant · Answer

We need to find What is the probability of flipping a fair coin three times and the coin landing on heads on exactly two flips

Coin is tossed 3 times => Total number of cases =  2^3  = 8

To find the cases in which the coin lands on exactly two flips we need to select two places out of three _ _ _ in which we will get Heads

This can be done using 3C2 ways =  \frac{3!}{2!*(3-2)!}  =  \frac{3*2!}{2!*1!}  = 3 ways

=> P(2H) =  \frac{3}{8}

So,  Answer will be A 
Hope it helps!

Watch the following video to learn How to Solve Probability with Coin Toss Problems

https://www.youtube.com/watch?v=LRURv38kZw8

jassonadder · Answer

When you flip a coin three times, you have a total of 23 = 8 possible outcomes.
You want exactly two heads.

Let's list the outcomes with exactly two heads:

HHT

HTH

THH

That’s 3 outcomes that match.

So, the probability = (Number of favorable outcomes) ÷ (Total outcomes) = 3/8.

If you use a Flip 3 coins simulator, you can easily test it out — you’ll see that getting exactly two heads happens about 3 times out of every 8 flips.

Thus, the correct answer is A. 3/8!

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