# of hardback copies sold after the first paperback copy sold = x
# of paperback copies sold = 9x
Total number of copies sold = 36,000 + 10x = 441,000
x = 40,500
# of paper copies sold = 364,500
o my.. i see my mistake .. the reason why i couldn't get the answer was from a substraction mistake in the beginning.
The greater the sacrifice, the greater the Victory