A set of numbers has the property that for any number t in the set, t + 5 is in the set. If -1 is in the set, which of the following must also be in the set?
I. -3
II. 4
III. 5	Pick
A) I only  B) II only  C) I and II only  D) II and III only  E) I, II, and III
The question is which of the followingmustbe in the set, notcouldbe in the set.   If -1 is in the set so must be   -1+5= 
<gadget id="calculator">  -1+5</gadget>
<output>4</output>
4, as 4 is in the set so must be   4+5= 
<gadget id="calculator">  4+5</gadget>
<output>9</output>
9, as 9 is in the set so must be   9+5= 
<gadget id="calculator">  9+5</gadget>
<output>14</output>
14 and so on.   Answer: II only.
<result>B</result>
A set of numbers has the property that for any number t in the set, t + 5 is in the set. If -1 is in the set, which of the following must also be in the set?
I. -3
II. 4
III. 5