Library / UKMT Senior Mathematical Challenge /48 of 212

UKMT Senior Mathematical Challenge, 2017

Algebra Difficulty 1.0 Junior Find the answer United Kingdom

The positive integer $k$ satisfies the equation $\sqrt{2} + \sqrt{8} + \sqrt{18} = \sqrt{k}$ . What is the value of $k$ ?

(A) $28$ (B) $36$ (C) $72$ (D) $128$ (E) $288$

We don't reproduce this publisher's solutions. Their own solution is here — work the problem first.

Want a route through all this instead of an archive? The track puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.

Source: UK Mathematics Trust, licensed © UK Mathematics Trust; past papers published free at ukmt.org.uk. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.