Answer: 437,500 copies
Explanation:
42,000 copies were sold in the first month and this is 9.6% of the total that have been sold till date:
To find the total that have been sold till date, assume the amount to be x.
Expression will be:
9.6%x = 42,000
x = 42,000 / 9.6%
x = 42,000 / 0.096
x = 437,500 copies
437,500 copies have been sold to date.