If t,u, and v are positive integers and 2t=2u+2v, which of the following must be true?
i. t=u
ii. u is not equal to v
iii. t > v
Select:  A) None  B) I only  C) II only  D) III and I  E) III only
Notice two things: 1. we are asked to find out which of the following MUST be true, not COULD be true and 2. t, u, and v are positive integers.   Given: 2st=2u+2v --&gt; t=u+v. Now, since s, u, and v are positive integers then s is more than either u or v, so I is never true and III is always true. As for II: it's not necessarily true, for example 4=2+2. So, we have that only option III must be true.   Answer: III only
<result>E</result>
If t,u, and v are positive integers and 2t=2u+2v, which of the following must be true?
i. t=u
ii. u is not equal to v
iii. t > v