If Nathan flips a coin 6 times, what is the probability that he gets exactly 3 heads?
Can someone please explain how to use combination logic in this question.
Regards
Karishma Duggal
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Combinations + Probability question
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karishma315
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P = (good outcomes)/(all possible outcomes).karishma315 wrote:If Nathan flips a coin 6 times, what is the probability that he gets exactly 3 heads?
Can someone please explain how to use combination logic in this question.
Regards
Karishma Duggal
All possible outcomes:
For each of the 6 flips, there are 2 options: heads or tails.
To combine the 2 options for each of the 6 flips, we multiply:
2*2*2*2*2*2 = 64.
Good outcomes:
From the 6 flips, any combination of 3 can yield exactly 3 heads.
Number of ways to choose 3 flips from 6 options = 6C3 = (6*5*4)/(3*2*1) = 20.
Resulting probability:
(good outcomes)/(all possible outcomes) = 20/64 = [spoiler]5/16[/spoiler].
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Hi Karishma,
When posting PS questions, you should make sure to post the ENTIRE prompt (with the 5 answer choices). In certain situations, the answer choices can provide a big 'clue' as to how to solve the question. In addition, sometimes the answer choices are so 'spread out' that you can take advantage of that spread and logically eliminate answers (as being too big, too small, or otherwise incorrect for some other logical reason). Since you didn't post the 5 answers, we're forced to approach this question mathematically (which can sometimes be the least efficient/slowest way to get to the correct answer).
GMAT assassins aren't born, they're made,
Rich
When posting PS questions, you should make sure to post the ENTIRE prompt (with the 5 answer choices). In certain situations, the answer choices can provide a big 'clue' as to how to solve the question. In addition, sometimes the answer choices are so 'spread out' that you can take advantage of that spread and logically eliminate answers (as being too big, too small, or otherwise incorrect for some other logical reason). Since you didn't post the 5 answers, we're forced to approach this question mathematically (which can sometimes be the least efficient/slowest way to get to the correct answer).
GMAT assassins aren't born, they're made,
Rich
