Our club has 20 members, 10 boys and 10 girls.  In how many ways can we choose a president and a vice-president if they must be of different gender?
Question:
Our club has 20 members, 10 boys and 10 girls.  In how many ways can we choose a president and a vice-president if they must be of different gender?
Answer:
Let's think step by step.

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Our club has 20 members, 10 boys and 10 girls.  In how many ways can we choose a president and a vice-president if they must be of different gender?
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