The two roots of the quadratic equation x2 - 85x + c = 0 are prime numbers. What is the
value of c? Options:  A) 84  B) 166  C) 332  D) 664  E) 1328
Assuming that two prime numbers x1 and x2 are the solutions, then x1 + x2 = 85.   Since 85 is an odd number, either x1 or x2 must be an even number. The only even prime   number is 2. Therefore, one number must be 2 and the other 83. Hence c = 2 *83= 
<gadget id="calculator">2 *83</gadget>
<output>166</output>
166.   correct answer 166
<result>B</result>
The two roots of the quadratic equation x2 - 85x + c = 0 are prime numbers. What is the
value of c?