9C3

Question

9C3

anonymous · Answer

nCr = n!/[r!(n - r)!]
Just plug it in or use your graphing calculator

anonymous · Answer

i have the equation, i just get stuck somewhere. thanks anyway

jim_thompson5910 · Answer

where are you getting stuck?

anonymous · Answer

ive got it thanks. I got 84 as an answer. hope thats right!!!

jim_thompson5910 · Answer

that is correct

anonymous · Answer

Thanks. Are you able to help me with a tree diagram

jim_thompson5910 · Answer

sure go for it

jim_thompson5910 · Answer

did you get my message?

anonymous · Answer

mini license plate for a toy car must consist of a letter followed by two numbers. Each letter must be a B, C or D. Each number must be a 5 or 6. Repetition of digits is permitted. 


okay so i started with my B C D lined up diagonally.
do I say

B15 C15 D15
B25 C25 D25
B35.....
B45
B55
B16
B26
B36
etc

then keep going for each letter C  and D with 10 options for each letter? I hope I explained what I did well

jim_thompson5910 · Answer

how are you getting the numbers 1, 2, 3, etc?

jim_thompson5910 · Answer

It says "Each number must be a 5 or 6" so the numbers 1, 2, 3, 4 can't be used

anonymous · Answer

oohhhh i guess i was thinking only one had to be a 5 or a 6. i read into it incorrectly

jim_thompson5910 · Answer

so the tree would look like this

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