if the probability that A will be alive in 20 years is 0.7 and the probability that B will be alive in 20 years is 0.5, find:
the probability that they both will be alive in 20 years
the probability that only one is alive in 20 years
I would think the total probability for both being alive is 0.7 * 0.5. The probability for no one being alive is 0.3 * 0.5. The probability for only one being alive is 1 - (0.7 * 0.5) - (0.3 * 0.5).
