12th Canadian Mathematical Olympiad Problems 1980

12th Canadian Mathematical Olympiad Problems 19801.  If the 5-digit decimal number a679b is a multiple of 72 find a and b. 2.  The numbers 1 to 50 are arranged in an arbitrary manner into 5 rows of 10 numbers each. Then each row is rearranged so that it is in increasing order. Then each column is arranged so that it is in increasing order. Are the rows

Posted in: CMO