The probability that a customer buys a coffee is 0.6, and the probability that a customer buys a pastry is 0.5, independent of the coffee…

For independent events, the probability that both happen is the product of their probabilities: $0.6 \times 0.5 = 0.30$, choice C. Choice A (0.55) is the average of the two probabilities, which has no meaning here. Choice B (1.10) adds the probabilities, giving a value above 1, which is impossible for a probability. Choice D (0.10) is the difference of the two probabilities. The word "both" combined with independence means multiply. Because the customer buys a coffee only 60% of the time, the chance of both must be less than 0.5.