Question: Jake trips over his dog 40% percent of mornings. 25% of the time he trips, he drops his coffee. What percentage of mornings does he NOT drop his coffee? Think carefully first, then make a decision:
First multiply the chance of each event happening to find the chance they both happen: 40% * 25% = 10%. Then subtract that percentage from 100% to find the percentage of the time Jake doesn't drop his coffee: 100% - 10% = 90%. So the answer is 90.