A small college with 1200 total students has a student government of 40 members. From its members, the student government will elect a president, vice president, secretary, and treasurer. No single member can hold more than 1 of these 4 positions. The permutation formula can be used to find the number of unique ways the student government can arrange its members into these positions. What are the appropriate values of n and r?
Q. A small college with 1200 total students has a student government of 40 members. From its members, the student government will elect a president, vice president, secretary, and treasurer. No single member can hold more than 1 of these 4 positions. The permutation formula can be used to find the number of unique ways the student government can arrange its members into these positions. What are the appropriate values of n and r?
Identify total number of members: Identify the total number of student government members n. n=40.
Determine positions to be filled: Determine the number of positions to be filled r. r=4 (president, vice president, secretary, and treasurer).
Use permutation formula: Use the permutation formula P(n,r)=(n−r)!n! to calculate the number of unique arrangements.
Plug in values: Plug in the values of n and r into the permutation formula. P(40,4)=(40−4)!40!.
Calculate factorials: Calculate the factorial of n and (n−r). 40!=40×39×38×…×1 and 36!=36×35×34×…×1.
Simplify permutation formula: Simplify the permutation formula by canceling out the common terms in the numerator and the denominator. P(40,4)=140×39×38×37.
Perform multiplication: Perform the multiplication to find the number of unique arrangements. P(40,4)=40×39×38×37.
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