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SEAMO 2018 — Paper E — Grade 9–10 Question 15

SEAMO · SEAMO 2018 — Paper E — Grade 9–10

Question 15

Given $a+2b+c=4$ for $a,b,c\in\mathbb R$, find the maximum of $ab+bc+ca$.
  1. $2$
  2. $4$
  3. $6$
  4. $8$
  5. None of the above