SOLUTION: P(7,r)=840

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Question 1172703: P(7,r)=840
Answer by greenestamps(13198) About Me  (Show Source):
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P(7,1) = 7
P(7,2) = 7*6 = 42
P(7,3) = 7*6*5 = 42*5 = 210
P(7,4) = 7*6*5*4 = 210*4 = 840

ANSWER: r=4