If c and t are positive integers, ct +c + t cannot be
Pick.
A) 5  B) 6  C) 7  D) 8  E) 9
Let ct + t + c = x   Add 1 on both sides:   ct + t + c + 1 = x + 1   t(c + 1) + c + 1 = x + 1   (c + 1)(t + 1) = x + 1   Minimum value of (c + 1) = 2   Minimum value of (t + 1) = 2   Hence x + 1 cannot be prime   Substitute x from the given options:   6 + 1= 
<gadget id="calculator">  6 + 1</gadget>
<output>7</output>
7 --&gt; prime --&gt; ct + t + s cannot be 6   Answer: 6
<result>B</result>
If c and t are positive integers, ct +c + t cannot be