Eight coins are tossed simultaneously. The probability of getting at l...
p = 1/2, q = 1/2, n = 8. Required probability = P (6 heads or 7 heads or 8 heads)
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Eight coins are tossed simultaneously. The probability of getting at l...
Understanding the Problem
When tossing eight coins, we want to calculate the probability of getting at least 6 heads. This includes the cases of getting 6, 7, or 8 heads.
Using the Binomial Probability Formula
The probability of obtaining exactly k heads in n tosses is given by:
- P(X = k) = C(n, k) * (p^k) * ((1-p)^(n-k))
Where:
- C(n, k) = n! / (k!(n-k)!)
- n = total number of coins (8 in this case)
- p = probability of getting heads (0.5 for a fair coin)
Calculating the Required Probabilities
We need to calculate the probabilities for k = 6, 7, and 8.
1. For 6 heads:
- C(8, 6) = 28
- P(X = 6) = 28 * (0.5^6) * (0.5^2) = 28 * (1/64) * (1/4) = 28/256
2. For 7 heads:
- C(8, 7) = 8
- P(X = 7) = 8 * (0.5^7) * (0.5^1) = 8 * (1/128) * (1/2) = 8/256
3. For 8 heads:
- C(8, 8) = 1
- P(X = 8) = 1 * (0.5^8) = 1/256
Total Probability of At Least 6 Heads
Now, we sum up the probabilities calculated above:
- P(X ≥ 6) = P(X = 6) + P(X = 7) + P(X = 8)
- P(X ≥ 6) = (28/256) + (8/256) + (1/256) = 37/256
Conclusion
Therefore, the probability of getting at least 6 heads when tossing 8 coins is 37/256, which corresponds to option 'B'.