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Can both events occur at the same time?
Mutually exclusive or not? Mutually exclusive.
Probability: 100 %
We want to determine whether the events are mutually exclusive and find the probability of their union. We will do these things one at a time.
Events that cannot occur at the same time are mutually exclusive. Mutually exclusive events have no outcomes in common. For example, because it is not possible to toss a coin and obtain heads and tails at the same time, these two events are mutually exclusive.
| Rules for Probability | |
|---|---|
| If A and B are mutually exclusive events, the probability that A and B will occur is P(AandB)=0. | If A and B are not mutually exclusive events, the probability that A and B will occur is P(AandB)≠0. |
Let A be getting heads
and B be getting tails
on a coin.
The coin can only land on one side, so we cannot get both heads and tails. Therefore, A and B are mutually exclusive events.
Now, we can find the probability that the coin lands on either heads or tails.
| Addition Rules for Probability | |
|---|---|
| If A and B are mutually exclusive events, the probability that A or B will occur is P(AorB)=P(A)+P(B). | If A and B are not mutually exclusive events, the probability that A or B will occur is P(AorB)=P(A)+P(B)-P(AandB). |
We know that the coin has 2 sides. Out of these, there is 1 side called heads and 1 called tails. Now, we can calculate P(A) and P(B). P(A)&=1/2 l← ← lHeads Total sides P(B)&=1/2 l← ← lTails Total sides Finally, considering that A and B are mutually exclusive events, let's calculate P(AorB).
P(A)= 1/2, P(B)= 1/2
Convert to percent
We found that P(Heads or tails) is equal to 100 %.