Tryingtodowell
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I JUST DONT GET THIS TOPIC
hardest ext 1 topic for me
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help -> combinations and permut (1 Viewer)
- Thread starter Tryingtodowell
- Start date
I JUST DONT GET THIS TOPIC
hardest ext 1 topic for me
WeiWeiMan
Well-Known Member
a. 9 choices for first digit (can't be 0), 9,8,7 etc for next digits
total = 9*9*8*7*6*5*4*3*2*1=9*9! = 3265920
b. 9 choices for first digit (can't be 0), 10 for each subsequent digit
total = 9 * 10^9 [9 other digits]