Sunday Times Teaser 2743 – Line-Up
by Nick MacKinnon
Published: 19 April 2015 (link)
I have arranged the numbers from 1 to 27 in a 3-by-3-by-3 cubical array. I have noticed that the nine numbers making up one of the faces of the cube are all primes. Also, I have searched through the array and written down the sum of any three numbers that are in a straight line. I have then calculated the grand total of all those line-sums. It turns out that the grand total is itself a perfect cube!
What is that grand total?