If r and t are positive integers, rt + r + t cannot be Choose the correct choice from the following answers
A) 5
B) 6
C) 7
D) 8
E) 9
Let rt + t + r = x   Add 1 on both sides:   rt + t + r + 1 = x + 1   t(r + 1) + r + 1 = x + 1   (r + 1)(t + 1) = x + 1   Minimum value of (r + 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; rt + t + r cannot be 6   Answer: 6
<result>B</result>
If r and t are positive integers, rt + r + t cannot be