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Question
A teacher wants to select the class monitor in a class of 30 boys and 20 girls, in how many ways can the monitor be selected if the monitor must be a boy? What is the answer if the monitor must be a girl?
Solution
Since the teacher wants to select a class monitor that must be a boy and there are 30 boys in a class.
∴ Total number of ways of selecting boy monitor
= 30 ways.
Since the teacher wants to select a class monitor that must be a girl and there are 20 girls in a class.
∴ Total number of ways of selecting girl monitor
= 20 ways.
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