For any positive number x, the function [x] denotes the greatest integer less than or equal to x. For example, [1] = 1, [1.367] = 1 and [1.999] = 1. If k is a positive integer such that k^2 is divisible by 45 and 80, what is the units digit of k^3/4000 ?  Choose the correct option
A) 0
B) 1
C) 27
D) 54
E) Cannot be determined
Factorization of 45 = 3*3*5   Factorization of 80 = 5 * 2^4   Means the smallest value of K is \sqrt{3^2*5*2^4}=3*5*2^2   K^3=3^3*5^3*2^6*X=3^3*2*4000*X where X can be any integer   K^3/4000=3^3*2*X=54X which obviously has different units digit depending on X   ANSWER:54
<result>D</result>
For any positive number x, the function [x] denotes the greatest integer less than or equal to x. For example, [1] = 1, [1.367] = 1 and [1.999] = 1. If k is a positive integer such that k^2 is divisible by 45 and 80, what is the units digit of k^3/4000 ?