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The number 100^2 has how many factors?

Solved 2 Answers 522 Views
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The number 100has how many factors?

A) 28

B) 25

C) 24

D) 20

E) 16

I know i can try to solve this problem by number crunching, but is there a better techinque or formula.

Official Answer

2 Answers

jaipster
2
Best answer
Yes there is here it goes
Number = (prime-factor1) ^ a x (prime-factor2)^2
Number of factors = (a+1)*(b+1)
for example 72 - 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, and 72. i.e. tweleve factors
72 = 2^3 * 3 ^ 2
total factors = (3 + 1) * (2 +1 ) => 12
Simarly in this questions
100^2 = (2^2 x 5 ^2) ^2  = (2^4) x (5^4)
a = 4, b = 4
= (4+1)(4+1)  
= 25
answered Jun 9, 2014 by Senior Associate (475 points)
selected Jun 9, 2014 by
1Comments
perfect thanx, exactly what is was looking for
commented Jun 9, 2014 by Partner (696 points)
flamingo
-2

the answer is 25

answered Jun 9, 2014 by Guru (5,599 points)
1Comments
obviousy i know the answer, i am looking for a better technique
commented Jun 9, 2014 by Partner (696 points)
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