SAT Math Practice Question #26506 - SATify | SATify
#26506
combinatorics
Relative Motion
hard
150 sec
Let S be the set 1,2,3,…,17. For a,b∈S, define a≻b to mean that either 0<a−b≤8 or b−a>8. How many ordered quadruples (w,x,y,z) of elements of S have the property that w≻x, x≻y, y≻z, and z≻w?