Product of all Numbers type of Question

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Product of all Numbers type of Question

by bkk_marc » Sun Nov 21, 2010 5:50 am
Hi, I been having problems with these types of questions lately. Anyone fancy giving me a few tips and approach strategy?

"If n is a positive internet, and the product of all integers from 1 to n is a multiple of 990, what is the lowest possible integer for n?

a.10
b.11
c.12
d.13
e.14

b
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by Rahul@gurome » Sun Nov 21, 2010 5:57 am
bkk_marc wrote:If n is a positive internet, and the product of all integers from 1 to n is a multiple of 990, what is the lowest possible integer for n?

a.10
b.11
c.12
d.13
e.14

b
990 = 11*10*9 = 2*3²*5*11

Therefore n must be such that the product of all integers from 1 to n must contain largest prime factor of 990, i.e. 11. Thus minimum value of n is 11.

The correct answer is B.
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