A group of students are taking Math, Psychology, and History: 20 students are taking Math 17 students are taking Psychology 15 students are taking History 9 students are taking Math & Psychology 8 students are taking Math & History 6 students are taking Psychology & History 3 students are taking all three classes How many students are in the group? There are ___ students in the group
Permutations and Combinations
If there are 5 dishes, they can be relished in any order at a time. In permutation, it should be in a particular order. In combination, the order does not matter. Take 3 letters a, b, and c. The possible ways of pairing any two letters are ab, bc, ac, ba, cb and ca. It is in a particular order. So, this can be called the permutation of a, b, and c. But if the order does not matter then ab is the same as ba. Similarly, bc is the same as cb and ac is the same as ca. Here the list has ab, bc, and ac alone. This can be called the combination of a, b, and c.
Counting Theory
The fundamental counting principle is a rule that is used to count the total number of possible outcomes in a given situation.
A group of students are taking Math, Psychology, and History:
20 students are taking Math
17 students are taking Psychology
15 students are taking History
9 students are taking Math & Psychology
8 students are taking Math & History
6 students are taking Psychology & History
3 students are taking all three classes
How many students are in the group?
There are ___ students in the group.
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