The probability that santa will come to the mall or your best friend will be there is 90% ⇒ A
Step-by-step explanation:
The addition rules of probability are:
- P(A or B) = P(A) + P(B) ⇒ mutually exclusive (events cannot happen at the same time)
- P(A or B) = P(A) + P(B) - P(A and B) ⇒ non-mutually exclusive (if they have at least one outcome in common)
∵ There is a 75% chance that santa will come to the mall that day
∴ P(santa) = 75% = 75 ÷ 100 = 0.75
∵ There is a 55% chance that your best friend will be at the mall
∴ P(friend) = 55% = 55 ÷ 100 = 0.55
∵ There is a 40% chance that your best friend and santa
will be at the mall
∴ P(friend and santa) = 40% = 40 ÷ 100 = 0.4
To find the probability that santa will come to the mall or your best friend will be there use the non-mutually exclusive addition rule
∵ P(friend or santa) = P(friend) + P(santa) - P(friend and santa)
∴ P(friend or santa) = 0.55 + 0.75 - 0.4
∴ P(friend or santa) = 0.9
- Change it to percentage by multiplying it by 100%
∴ P(friend or santa) = 0.9 × 100% = 90%
The probability that santa will come to the mall or your best friend will be there is 90%
Learn more:
You can learn more about the probability in brainly.com/question/9178881
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