If a positive integer n is divisible by both 2 and 5, then n must also be divisible by which of the following?
I. 10
II. 7
III. 40  Choices:  A) None  B) I only  C) II only  D) I and II  E) II and III
A multiple of 2 and 5 is also a multiple of 10, but not necessarily a multiple of 7 or 40.   The answer is I only.
<result>B</result>
If a positive integer n is divisible by both 2 and 5, then n must also be divisible by which of the following?
I. 10
II. 7
III. 40