For the experiment of tossing a coin three times, how do you find the probability of getting at least two heads?

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Answer 1 · 2017-08-22T08:17:25

$1/2$

Since we only have three throws it will be easier to list all possibilities, of 1st, 2nd and 3rd throws

$H =$ head

$T=$ Tail

$color(blue)(HHH)$

$color(blue)(HHT)$
$color(blue)(HTH)$
$color(blue)(THH)$

$T T H$
$THT$
$H T T$

$T T T$

Eight possibilities in all, and the requirement of at least two heads is shown in blue

$X=" number of heads"$

$P(X >=2)=4/8=1/2$

Answer 2 · 2017-08-22T08:19:38

1/2

total possible case :- HHH, HHT, HTH, THH, TTT, TTH, THT, HTT

At least two heads :- 4

so the probability of getting at least two head is 4/8 = 1/2