CBSE Class 11-science Answered

2) Union (AUB)- Denotes all the elements of the given sets taken once.

A U B = {2, 3, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 26, 28} 

Examples

1. From a survey of 100 college students, a marketing research company found that 75 students owned stereos, 45 owned cars, and 35 owned cars and stereos. a) How many students owned either a car or a stereo? b) How many students did not own either a car or a stereo?  METHOD: a) Start with a Venn Diagram and label the different categories: b) Fill in the number of students who own both cars and stereos, which would be in the intersection of the two sets: c) Fill in the remaining numbers for the two sets. In this case, since a total of 45 students own cars, and 35 have already been listed, then 45 - 35 = 10students own cars only. Similarly, since 75 students own stereos and 35 have already been listed, then 75 - 35 = 40 students who own stereos only: d) Finally, interpret and answer the questions: