30-[x+5 7/15]=18 9/20

х + 5 7/15 = 30 - 18 9/20 х + 5 7/15 = 11 11/20 х = 11 11/20 - 5 7/15 х = 11 33/60 - 5 28/60 х = 6 5/60 х = 6 1/12