Given P(J) = 0.18, P(K) = 0.37 and P(J or K) = 0.45, what is P(J and K)?

1. The addition rule gives 0.45 equal to 0.18 plus 0.37 minus the joint probability. 2. The two separate probabilities add to 0.55. 3. The joint probability is therefore 0.55 minus 0.45, which is 0.10. 4. Answering 0.55 reports the sum of the parts and skips the subtraction entirely. _Source: OpenStax Introductory Business Statistics (CC BY 4.0), Ch 3 "Probability Topics", section 3.3 Two Basic Rules of Probability_