MHB Is 106 = 9Cx correct for this combination problem?

[mathdad]

I found an interesting question online. It involves combination.

106 = 9Cx

I know the combination formula but can someone set it up for me?

Here is my endeavor:

106 = 9!/x!(9 - x)!

Is this correct?

 

[Wilmer]

106 = 9Cx

You sure that should be 106?

(9)C(x), x = 1 to 9:
9,36,84,126,126,84,36,9,1

 

[mathdad]

6C2 + 7C4 + 8C5 = 9Cx

 

[Wilmer]

6C2 + 7C4 + 8C5 = 9Cx

Says who?

 

[mathdad]

Says who?

I found this question online not from a textbook.

 

[Wilmer]

I gave you the possible solutions: none equals 106.

Can you give us the url of the site?

 

[Wilmer]

Here is my endeavor:
106 = 9!/x!(9 - x)!

The right side should be 9! / (x!(9 - x))
Do you see why the extra set of brackets is required?

Once more: there is NO SOLUTION = 106

 

[Greg]

106 = 9!/x!(9 - x)!

You need appropriate parentheses. The above should be

9!/(x!(9 - x)!)

 

[mathdad]

6C2 + 7C4 + 8C5 = 9Cx

6C2 = 15

7C4 = 35

8C5 = 56

15 + 35 + 56 = 9Cx

50 + 56 = 9Cx

106 = 9Cx

Do you see where 106 comes from?

 

[Wilmer]

6C2 + 7C4 + 8C5 = 9Cx
6C2 = 15
7C4 = 35
8C5 = 56
15 + 35 + 56 = 9Cx
50 + 56 = 9Cx
106 = 9Cx
Do you see where 106 comes from?

Doesn't matter where it comes from.
Look buddy, give us the link to where you found
this problem...else you're on your own...

 

[mathdad]

I found this problem in a facebook math group but there are so many that I truly don't recall the name of the group. This question is not so important. Thanks anyway.

 

[MarkFL]

Like Wilmer, I found that there is no natural number solution to that problem. W|A was able to return 2 numeric approximations, but with a problem like this, we expect natural numbers. Seeing the original problem would have helped to clear up the issue. :)

 

[Wilmer]

Sorry if I sounded exasperated Mr.RTCNTC.

I've seen quite a few "Facebook math posts" that are inaccurate...

 

[mathdad]

Can we just move on?