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Prime Factors

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Prime Factors

by umaa » Mon Aug 18, 2008 3:08 am
What is the lowest prime factor of the sum of all the numbers from 5 to 37, inclusive?

A) 3
B) 5
C) 7
D) 11
E) 37
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Re: Prime Factors

by sudhir3127 » Mon Aug 18, 2008 3:15 am
umaa wrote:What is the lowest prime factor of the sum of all the numbers from 5 to 37, inclusive?

A) 3
B) 5
C) 7
D) 11
E) 37
I go with A.

heres how

sum of all umbersfrom 5 to 37.

n/2 ( first term + last term )

n= 37-5+1=33

33/2*(5+37)
33*21 = 693

now 693 can be wrtitten as
3^2*7*11

hence the answer is 3.

hope it helps..
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by vishubn » Mon Aug 18, 2008 3:24 am
i AGREE WITH Sudhir ! i ended up doign the same thing

i think 3 is the lowest prome factor

Vishu
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