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positive integer n

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positive integer n

by vaivish » Sun Sep 21, 2008 12:01 pm
What is the positive integer n?
(1)For every positive integer m, the product m(m + 1)(m + 2) ... (m + n) is divisible by 16
(2) n^2 - 9n + 20 = 0


OA is c.
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Source: — Data Sufficiency |
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by mals24 » Sun Sep 21, 2008 12:11 pm
St 1 just tells us that (m+n)! is divisible by 16
It does not help us in finding a unique value for n----INSUFF

St 2 solving the equation we get two values for n, 4 & 5 ------INSUFF

Combining 1 & 2

Let m= 1
1. n=4
(m+n)!=(4+1)!=5!=120 is not divisible by 16

2.n=5
(5+1)!=(6!=720 is divisible by 16

Hence the value of n=5
The answer is C
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