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Prime Sum

by money9111 » Mon Feb 01, 2010 8:32 pm
The "prime sum" of an integer n greater than 1 is the sum of all the prime factors of n, including repetitions. For example, the prime sum of 12 is 7, since 12=2x2x3 and 2+2+3=7. For which of the following integers is the prime sum greater than 35?

a. 440
b. 512
c. 620
d. 700
e. 750

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by money9111 » Mon Feb 01, 2010 8:41 pm
OA C
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by thephoenix » Mon Feb 01, 2010 8:49 pm
we need to check div by aprime no. near to 35 , which are 29,31,37

a)440
the highest prime no it is div by is 11 occurring ones , infact its 11*4*5*2 prime sum=22

b)512 is 2^9 ps=18
c)620=31*2*5*10
prime sum >35
hence c
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