Probability: Problems Based on Coins

# Probability: Problems Based on Coins Video Lecture | Quantitative Aptitude for SSC CGL

## Quantitative Aptitude for SSC CGL

314 videos|170 docs|185 tests

## FAQs on Probability: Problems Based on Coins Video Lecture - Quantitative Aptitude for SSC CGL

 1. What is the probability of getting heads when flipping a fair coin?
Ans. The probability of getting heads when flipping a fair coin is 1/2 or 0.5. This assumes that the coin is unbiased and has an equal chance of landing on heads or tails.
 2. If I flip a fair coin three times, what is the probability of getting at least two heads?
Ans. To calculate the probability of getting at least two heads when flipping a fair coin three times, we can use the concept of combinations. There are 8 possible outcomes when flipping a coin three times: HHH, HHT, HTH, THH, HTT, THT, TTH, and TTT. Out of these, 4 outcomes have at least two heads (HHH, HHT, HTH, THH). Therefore, the probability is 4/8 or 0.5.
 3. What is the probability of getting exactly two tails when flipping a biased coin with a 60% chance of landing on heads?
Ans. When flipping a biased coin with a 60% chance of landing on heads, the probability of getting exactly two tails can be calculated using the binomial probability formula. The formula is P(X=k) = (n choose k) * p^k * (1-p)^(n-k), where n is the number of trials, k is the number of successful outcomes, and p is the probability of success. In this case, n=3 (3 coin flips), k=2 (getting exactly two tails), and p=0.4 (since tails has a 40% chance). Plugging these values into the formula, we get P(X=2) = (3 choose 2) * 0.4^2 * (1-0.4)^(3-2) = 3 * 0.16 * 0.6 = 0.288 or 28.8%.
 4. If I have 5 fair coins, what is the probability of getting at least one head when flipping all of them?
Ans. To calculate the probability of getting at least one head when flipping 5 fair coins, we can use the concept of complementary probability. The complementary probability of an event A is equal to 1 minus the probability of the event not occurring (A'). In this case, the probability of getting at least one head is equal to 1 minus the probability of getting all tails. Since the probability of getting tails on a fair coin flip is 1/2, the probability of getting all tails when flipping 5 coins is (1/2)^5 = 1/32. Therefore, the probability of getting at least one head is 1 - 1/32 = 31/32 or approximately 0.969.
 5. If I flip a fair coin four times, what is the probability of getting more tails than heads?
Ans. To calculate the probability of getting more tails than heads when flipping a fair coin four times, we can consider the possible outcomes. Out of the 16 possible outcomes (2^4), there are 6 outcomes where there are more tails than heads: TTTT, TTTH, TTHT, HTTT, THTT, and HTTT. Therefore, the probability is 6/16 or 0.375.

## Quantitative Aptitude for SSC CGL

314 videos|170 docs|185 tests

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