What is greatest positive integer n such that 2^n is a factor of 12^9?  Choose the correct choice from the following answers.
A) a)10
B) b)18
C) c)16
D) d)20
E) e)60
The given number is 12^9   =(2*2*3)^9   =(2^18)*(3^9)   So the greatest possible value for n such that 2^n can be factor of given number is 18.   Answer b)18
<result>B</result>
What is greatest positive integer n such that 2^n is a factor of 12^9?