Carcass wrote:
What is the probability of flipping a fair coin two times and the coin landing on heads on both flips?
A. 1/8
B. 1/4
C. 1/2
D. 3/8
E. 3/4
Approach #1: Probability rulesP(both heads) = P(1st toss is heads
AND 2nd toss is heads)
= P(1st toss is heads)
x P(2nd toss is heads)
= 1/2
x 1/2
= 1/4
Answer: B
Approach #2: CountingP(both heads) = (
# of outcomes in which both tosses are heads)/(
total # of possible outcomes)
Since there are so few outcomes, let's just list them:
- 1st toss is heads and 2nd toss is heads- 1st toss is heads and 2nd toss is tails
- 1st toss is tails and 2nd toss is heads
- 1st toss is tails and 2nd toss is tails
total # of possible outcomes = 4Among those
4 possible outcomes, only
1 outcome meets the condition that both tosses are heads
So, P(both heads) =
1/
4Answer: B
Cheers,
Brent