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SEAMO 2027 - Paper D - SET 04 - Self-study Question 3

SEAMO · SEAMO 2027 - Paper D - SET 04 - Self-study

Question 3

Let $k$ be a real number. Find the least value of $k$ such that the following inequality is correct:
$$\sqrt{x-2}+\sqrt{7-x}\le k.$$

Interpretation for this practice: the inequality must hold for every real $x$ for which both radicals are defined, namely $2\le x\le7$. The source leaves this quantifier implicit.
  1. $\sqrt5$
  2. $\sqrt{10}$
  3. $\sqrt2+\sqrt3$
  4. 3
  5. $2\sqrt3$