in how many ways can a team of 5 members be formed from a group of 10 scientists consisting of 4 chemists and 7 physicists if a particular chemist and particular physicist can't be both in the research team? answer is said to be C(11,5) - C(9,3) which i don't understand where C(9,3) came from O:

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anonymous · Answer

Did u typed the full question?

anonymous · Answer

i think you must use combination in answering this problem..

anonymous · Answer

@jedai17 i'm aware of that, but how?