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IKMC 2015 - Grades 9-10 - Self-study Question 18

IKMC · IKMC 2015 - Grades 9-10 - Self-study

Question 18

Both roots of $x^2-85x+c=0$ are prime. What is the digit sum of c?
  1. 12
  2. 13
  3. 14
  4. 15
  5. 21