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Question
In how many ways can a student choose a programme of 5 courses if 9 courses are available and 2 specific courses are compulsory for every student?
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Solution
2 courses are compulsory out of the 9 available courses. There are 7 more courses.
So, we need to choose 3 courses out of 7 courses.
∴ Required number of ways =\[{}^7 C_3 = \frac{7}{3} \times \frac{6}{2} \times \frac{5}{1} = 35\]
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