Rhonda J.

asked • 01/02/14

There are 5 members in a group. 3 members are can be chosen to go on a trip. How many different groups of 3 can there be?

Word problem that has me confused

4 Answers By Expert Tutors

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Robert J. answered • 01/02/14

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4.6 (13)

Certified High School AP Calculus and Physics Teacher

Rhonda J.

Thank you...I am not sure how the equation works.  But, I do understand the answer.
 
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01/02/14

Steve S.

5*4*3 = number of groups where order matters
 
3*2*1 = number of ways to order each group
 
(5*4*3) / (3*2*1) = number of groups where order doesn't matter
 
5*4*3 = 5*4*3*2*1 / (2*1) = 5! / 2!
3*2*1 = 3!
 
(5*4*3) / (3*2*1) = 5! / 2! / 3! = 5! / (2! * 3!) = 5C3 = 5C2
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01/02/14

Robert J.

The number of ways you pick 3 out of 5 is the same as you pick 2 out of 5 if the order doesn't matter.
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01/03/14

Grigori S. answered • 01/03/14

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0 (0)

Certified Physics and Math Teacher G.S.

Steve S. answered • 01/02/14

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5 (3)

Tutoring in Precalculus, Trig, and Differential Calculus

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