Turn on thread page Beta
    • Thread Starter

    A 5*5 square is divided into 25 unit squares. One of the numbers 1,2,3,4,5 is inserted into each of the unit squares, in such a way that each column, each row and two diagonals contains the numbers 1-5 once and only once. The sum of the numbers immediatley below the diagonal from top left to bottom right is called the score.

    Show that it is impossible for the score to be 20
    What is the highest possible score?

    The first part can only be done using four 5's and that doesn't follow the rules because one of the diagonals must also contain a 5 meaning that there are two 5's in one column.

    For the second part, is it best to just try different value's say 4,5,5,5 Or set the score to 19,18,17....and see whether it's possible for them to work?

    I don't understand the different between your two methods for the last section, but yes, it is the correct method
Submit reply
Turn on thread page Beta
Updated: October 19, 2008

University open days

  • Sheffield Hallam University
    City Campus Postgraduate
    Wed, 17 Oct '18
  • Staffordshire University
    Nursing and Midwifery Undergraduate
    Wed, 17 Oct '18
  • Teesside University
    Undergraduate open day Undergraduate
    Wed, 17 Oct '18
Who is most responsible for your success at university
Useful resources

Make your revision easier


Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here


How to use LaTex

Writing equations the easy way


Best calculators for A level Maths

Tips on which model to get

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.