Combinations question (1 Viewer)

[MrTroll]

A commitee of 6 is to be selected from a group of 10 people of which A and B are two. How many committees can be formed excluding A if B is included?

 

[Amogh]

Think it through logically...
So we put B into the committee, that leaves 9 people and 5 spots.
Oh but, A can't be included.
So we really have 8 people and 5 spots. 8 Choose 5.
Voila!

(It'd be so awkward if I'm wrong...)

 

[MrTroll]

Think it through logically...
So we put B into the committee, that leaves 9 people and 5 spots.
Oh but, A can't be included.
So we really have 8 people and 5 spots. 8 Choose 5.
Voila!

(It'd be so awkward if I'm wrong...)

thats wat i did as well. but it is wrong.

 

[taeyang]

lol.

 

[MrTroll]

lol.

wats so funny

 

[taeyang]

"(It'd be so awkward if I'm wrong...)"

 

[MrTroll]

"(It'd be so awkward if I'm wrong...)"

lol yeah. i luv how he set it out like a genius and finished with a 'voila' but he failed. taeyang do u no how to do this?

 

[MrTroll]

But surely 8C5 is right though?

fitzpatrick says it is 140. and 8C5 = 56.

 

[taeyang]

To be honest, I thought the answer was 8C5 as well, I dunno, 8C4 x 2 gives you 140.

 

[tambam]

A commitee of 6 is to be selected from a group of 10 people of which A and B are two. How many committees can be formed excluding A if B is included?

The question is asking for all the committees which can be formed, but the condition is that if B is included, A must be excluded. The group can have neither A nor B, just A or just B

Therefore, your solution is the total combinations, 10C6, minus all combinations where A and B are together, 8C4.
This gives an answer of 140

 

[MrTroll]

The question is asking for all the committees which can be formed, but the condition is that if B is included, A must be excluded. The group can have neither A nor B, just A or just be.

Therefore, your solution is the total combinations, 10C6, minus all combinations where A and be are together, 8C4.
This gives an answer of 140

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misread question. lol tnks.

 

[username30]

it's a really badly worded question.

You don't really know if "B must be included" or "if B is included, A must be excluded"