- #1

mr_coffee

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- 1

It says:

Each symbol in braille code is represened by a rectangular arrangement of six dots. Given that a least 1 dot of the 6 must be raised, how many symbols can be represented in brail?

I'm thinking I have to use combinations becuase the multipcation rule won't work..the combination formula is the following:

Choosing r items out of n,

n!/r!(n-r)!

So I can choose 6 symbols, but if at least one has to be raised, that means all 6 can be raised, so would i have 12 possibilites?

then i was thinking maybe the total possilbites of r items would be

2^12 because the dot is either up or down.

So would the answer be 2^12 = 4096 symbols?

That seems way too big...

so the other answer might be:

12!/2!(10)! = 66. that sounds more like it but I'm still not sure if its correct.

Any help would be great