Why is this the answer?
A parking lot has 100 red and blue cars in it.
- 40% of the cars are red.
- 70% of the red cars have radios.
- 80% of the blue cars have radios.
What is the probability of selecting a car at random that is either red or has a radio?
I calculated it as:
.40 + .70 - (.40 X .70) = .82
I got this wrong and here is the explanation:
P(red or radio) = P(red) + P(radio) – P(red and radio) = 0.40 + 0.76 – 0.28 = 0.88 or 88%.
Where did the .76 come from?
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