alleryStart learning →Carlos scores each of two attempts with chance 0.65, and scores both with chance 0.585. What is the chance he scores at least one?
A1.300
B0.065
C0.845
D0.715
Answer & Solution
Correct answer: D. 0.715
1. At least one means the first or the second or both.
2. The rule for or adds the two chances, then removes the overlap counted twice.
3. Add 0.65 and 0.65 to get 1.30.
4. The overlap is the chance of both, which is 0.585.
5. Subtract 0.585 from 1.30.
6. 1.30 minus 0.585 is 0.715.
7. Answering 1.300 forgets to remove the overlap, and no chance can exceed one.
8. Answering 0.065 subtracts the two given chances from each other, which the rule never asks for.
_Source: OpenStax High School Statistics (CC BY 4.0), Ch 2 "Descriptive Statistics" and Ch 3 "Probability Topics", section 3.3 Two Basic Rules of Probability_
Keep practising Probability Topics
Browse all Probability Topics questions for CBEST, or explore more Mathematics topics.
Related questions
Sort the draws by independenceMerge the coin chancesA fair die is rolled. Event A is an even face and event B is a face below four. Given thatA bag holds four green, three red and two yellow marbles. Two are drawn without replacemenThree red and eight blue balls sit in an urn, and two are drawn with replacement. In how mAn urn holds 3 red and 8 blue balls. Two are drawn one at a time with replacement. How manIn a class, 60 percent are female and 50 percent have long hair. If those two facts were iCarlos scores on 65 percent of his shots, and is 90 percent likely to score his second giv