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Dinda Erliananda Teaching Materials – SMA Class XII – Enumeration Rules

3. Addition Rule

If an event consists of n independent stages in which the first event can be
performed in different ways, the second event can be performed in different ways, and

so on until the nth event can be performed in different ways,

then the total of the events is different. It's the Addition Rule.

Example 2:
To take part in a math competition, a school is required to send 1 representative student.

If in the final stage of selection 3 boys and 2 girls are selected, determine how many

ways the school chooses its representatives to participate in the math competition.

Answer:
These events are mutually exclusive events because the first event is not followed by

the second event or the event is not a paired event. Therefore, in answering this

question, the addition rule is used.
So, the number of ways a school chooses its representatives to take part in a math

competition is 3 + 2 = 5 different ways.

LET'S WORK!
Watch the video below and pay attention carefully, then solve the problem that has

given in the video.

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