Bunuel wrote:
For a positive integer n, the function @n represents the product of all even numbers that lie between n and 2n, exclusive. For example, @6 = 8*10. If k is a positive integer and the greatest prime factor of @k is 17, which of the following cannot be the value of k?
I. 9
II. 18
III. 32
A. I only
B. II only
C. III only
D. I and III only
E. II and III only
@n = product of even numbers between n and 2n.
@n must contain all even numbers.
for @k to have 17 as a prime factor, it must have 34 as one the numbers but should not include 38 included within
k.
K = 9: @k will not include 34. not possible
k = 18; @k range from 20 - 34. possible
k = 32; @k range from 34-62. not possible because it includes 38 which shifts greater prime factor to be more than 17 to 31
ans: D