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