Easy, it is 1. I hope that helps =D
It could either be 11:9 or 11.../9...
(The dots stand for what the problem is talking about,for example 11 hot dogs per $9
<h3>
Answer: A. 21</h3>
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C(n, r) = (n!)/(r!*(n-r)!) is the combination formula
C(7, 5) = (7!)/(5!*(7-5)!)
C(7, 5) = (7!)/(5!*2!)
C(7, 5) = (7*6*5!)/(5!*2!)
C(7, 5) = (7*6)/(2!) ..... note the "5!" terms divided and canceled
C(7, 5) = (7*6)/(2*1)
C(7, 5) = 42/2
C(7, 5) = 21
89 is prime 16 is composite 17 is prime 25 is composite
