In a long series of coffee orders, it is determined that 70% of coffee drinkers use cream, 55% use sugar, and 35% use both.

A Venn Diagram. One circle is labeled C (0.35) and the other is labeled S (0.20). The shared area is labeled 0.35. The area outside of the diagram is labeled 0.10.

Suppose we randomly select a coffee drinker. Let C be the event that the coffee drinker uses cream and S be the event that the coffee drinker uses sugar.

What is the probability that a randomly selected coffee drinker does not use sugar or cream?

ANSWER IS ⇒ 0.10

What is the probability that a randomly selected coffee drinker uses sugar or cream?

ANSWER IS ⇒ 0.90