How many of the positive divisors of 480 are also multiples of 4 not including 480? Options:
A) 15  B) 16  C) 19  D) 20  E) 24
480 = 2^6 * 3 * 5 = (4) * 2^3 * 3 * 5   Besides (4), the exponents of 2, 3, and 5 are 3, 1, and 1.   There are (3+1)(1+1)(1+1) = 16 ways to make multiples of 4.   We must subtract 1 because one of these multiples is 480.   The answer is 15.
<result>A</result>
How many of the positive divisors of 480 are also multiples of 4 not including 480?