A coin is tossed 7 times. Find the probability of getting more heads than tails in all 7 tosses?
A. 1/2
B. 63/128
C. 4/7
D. 61/256
E. 63/64
I'm confused how to set up the formulas here. Can any experts help?
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A coin is tossed 7 times. Find the probability of getting mo
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Ways to get MORE HEADS THAN TAILS:ardz24 wrote:A coin is tossed 7 times. Find the probability of getting more heads than tails in all 7 tosses?
A. 1/2
B. 63/128
C. 4/7
D. 61/256
E. 63/64
4 heads, 3 tails
5 heads, 2 tails
6 heads, 1 tail
7 heads
Ways to get MORE TAILS THAN HEADS:
4 tails, 3 heads
5 tails, 2 heads
6 tails, 1 head
7 tails
Notice that the blue outcomes and the red outcomes are perfectly parallel.
Implication:
Since P(H) on any flip is the same as P(T) on any flip, the probability of getting the blue outcomes must be equal to the probability of getting the red outcomes.
Thus:
P(more heads than tails) = 1/2.
P(more tails than heads) = 1/2.
The correct answer is A.
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
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