Question

an unbaised coin is tossed 4 times. what is the probability of getting at least two heads​

Answer 1

Given:-

• An unbaised coin is tossed 4 times.

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To find:-

• Probability of getting at least two hheads.

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Solution:-

★Probability of head = Probability of Tails = 1/2

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Probability of 2 heads and two tails:-

$\large{\boxed{\boxed{\sf{Case\: 1}}}}$

head, head, tails, tails = (1/2) × (1/2) × (1/2) × (1/2) = 1/16

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$\large{\boxed{\boxed{\sf{Case\: 2}}}}$

head, tails,head, tails = (1/2) × (1/2) × (1/2) × (1/2) = 1/16

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$\large{\boxed{\boxed{\sf{Case\: 3}}}}$

head, tails, tails,head = (1/2) × (1/2) × (1/2) × (1/2) = 1/16

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$\large{\boxed{\boxed{\sf{Case\: 4}}}}$

tails,head, tails,head = (1/2) × (1/2) × (1/2) × (1/2) = 1/16

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$\large{\boxed{\boxed{\sf{Case\: 5}}}}$

tails, tails,head,head = (1/2) × (1/2) × (1/2) × (1/2) = 1/16

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$\large{\boxed{\boxed{\sf{Case\: 6}}}}$

tails, head,head,tails = (1/2) × (1/2) × (1/2) × (1/2) = 1/16

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→ Probability of 2 heads and two tails = 6 cases × (1/16) = 3/8 = 38%

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Hence,

• the probability of getting at least two heads is 38%.