The following is proposed as number 1175 in the Problem Department of
It is known that the numbers 14529; 15197; 20541; 38911; and 59619 are
multiples of 167. Without actually calculating, prove that the determinant
of the 5-by-5 matrix A is also a multiple of 167, where
multiples
In this problem we are given a 5-by-5 matrix and calculating its determinant
by hand is tedious. We look at a similar problem, but with smaller
dimension. First, we look at examples involving 2-by-2 matrices to see if this
case holds: if we are given two two-digit integers (say, x = a1a2 and y = b1b2)
and if these integers are divisible by a given integer k, is it true that k also
divides the determinant of the matrix