Maths Olympiad Prep

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Combinatorics Difficulty 2.7 Junior Find the answer Canada

In the diagram, each letter from AA to HH is equal to a different integer from 11 to 88.Figure 0Also, HH is a perfect square and is 11 more than DD 55 and 88 are in the same row CC is a multiple of both GG and DD BB is the largest prime number in the set The value of B+GB+G is even What is the value of FF?

Pick one

Solution

HH is a perfect square and is 11 more than DD. The perfect squares from 11 to 88 inclusive are 11 and 44. Since HH is one more than DD, HH cannot be equal to 11 (since D0D\neq0), and so H=4H=4 and D=3D=3. BB is the largest prime number in the set, and so B=7B=7. CC is a multiple of both GG and DD. Since D=3D=3, then C=6C=6 and GG is equal to either 11 or 22 (since 66 is a multiple of each of these). The value of B+GB+G is even, and since B=7B=7, then G=1G=1. The letters which have not been assigned values are AA, EE and FF, and the integers which have not been assigned are 22, 55 and 88. Since 55 and 88 are in the same row and AA and EE are the two remaining unassigned letters that are in the same row, then AA and EE are 55 and 88 in some order, which leaves F=2F=2.

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Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.