If s and t are positive integers, st + s + t cannot be	Pick one
A) 5 B) 6 C) 7 D) 8 E) 9
Let st + t + s = x   Add 1 on both sides:   st + t + s + 1 = x + 1   t(s + 1) + s + 1 = x + 1   (s + 1)(t + 1) = x + 1   Minimum value of (s + 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; st + t + s cannot be 6   Answer: 6
<result>B</result>
If s and t are positive integers, st + s + t cannot be