Latest Maths Olympiad Aptitude Question SOLUTION: How many 6-tuples (a1, a2, a3, a4, a5, a6) are there such that each of a1, a2, a3, a4, a5, a6 is from the set {1, 2, 3, 4} and the six expressions a2 j - ajaj +1 + a2 j+1 for j = 1