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#1
Report Thread starter 12 years ago
#1
There is a lottery where each ticket has 5 different letters printed on it (So there are 65780 tickets in total).

Tickets which match 3 numbers win £10.

Find the number of tickets which win £10.

I thought it would be 5C3 (For the three you match) x 21 (number of possible letters for letter #4) x 20 (number of possible letters for letter #5) = 4200.

Apparently the answer is 2100, what did I do wrong?
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#2
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i would agree on 4200...
hmmm
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#3
Report Thread starter 12 years ago
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Can anybody see how to get 2100 as the answer?
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#4
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Wait i got it!
It's 5C3 multiplied by 21C2
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#5
Report Thread starter 12 years ago
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Ohhhh, how obvious was that. Thanks!
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