Are the following random variables binomial random variable?Explain why or why not?

Question

i.Forty percent of all airline pilots are over 40 years of age.Out of a random sample of 15 pilots,let the random variable X be the number of pilots who are over 40 years of age.

ii.Suppose a salesperson make sales to 20% of her customers.One day she countered her customers until she made a sale.Let X be the number of customers until her first sale.

iii.a room contains six women and four men.Three people are selected to form a committee.Let the random variable X be the number of women on the committee.

Answer 1

i is binomial, because every pilot is over 40 years or not.

I'm not quite sure about ii and iii. I thnk they are not binomial.

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