Answer:
15*2/3=10
10*2/3=20/3
20/3*2/3=40/9
40/9*2/3=80/27
80/27*2/3=160/81
160/81*2/3=480/243
480/243*2/3=960/729
960/729*2/3=1920/2187.
=1920/2187
