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Problem 354

Algebra Difficulty 2.0 Prove it UKMT Senior Kangaroo · United Kingdom · 2021

The geometric mean of a set of nn positive numbers is defined as the nn-th root of the product of those numbers. Yasmeen writes down a set of four numbers which have a geometric mean of 20482048. Zak writes down a set of four numbers which have a geometric mean of 88. What is the geometric mean of the combined set of the eight numbers written by Yasmeen and Zak?

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