Mustered up

Probability Level 1

A store features 5 varieties of mustard. If you want 2 types on your sandwich, how many possibilities are there?

Assume that getting types A and B is the same as getting types B and A.


The answer is 10.

Denton Young by Denton Young , 47, USA

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4 solutions

Andy Pato
Jun 25, 2016

Is it a fluke that n(n-1)/2 works here?

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Shourjya Basu
Jun 18, 2016

5 {C {2}} = 10

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Ashish Menon
May 31, 2016

Answer is 0 5 C 2 = 10 {\phantom{0}}^5C_2 = \color{#69047E}{\boxed{10}} .

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How exactly do combinations work? Afraid I've forgotten.

Calvin Soueid - 4 years, 12 months ago

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0 5 C 2 = 5 ! 2 ! ( 5 − 2 ) ! = 120 2 × 3 ! = 60 6 = 10 {\phantom{0}}^5 C_2 = \dfrac{5!}{2!(5-2)!} = \dfrac{120}{2 × 3!} = \dfrac{60}{6} = \color{#3D99F6}{\boxed{10}} .
Remember this?

Ashish Menon - 4 years, 12 months ago
Noel Lo
Jun 5, 2015

5 C 2 = 10 5C2 =\boxed{10} .

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Why not 20?

Vinícius Máximo Secanho - 6 years ago

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Putting Mustard X and Mustard Y together is the same as putting Mustard Y and Mustard X together.

Vishnu Bhagyanath - 6 years ago

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