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The probability that a family has children is 0.73, the probability that a family has children and
owns an iPhone is 0.06, and the probability that a family has children or owns an iPhone is 0.85.
Calculate the probability a family owns an iPhone.
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P(or) = P(C) + P(i) - P(and)
0.85 = 0.73 + 0.06 - P(and)
P(and) = 0.73 + 0.06 - 0.85 = 0.79 - 0.85 = -0.06.
The probability can not be negative --- HENCE, the problem is posed INCORRECTLY.
This problem is a FAKE or a TRAP, or BOTH.
It describes a case which NEVER may happen.