Answer:
520,896 copies have been sold to date
Explanation:
We know that in one month it sold 34,900 books, which represents 6.7%
To know how much is 100% we have to divide this number by 6.7 and then multiply it by 100
34,900 / 6.7 = 5208.9552
5208.955 * 100 = 520,895.52
if we round to the nearest whole number
520,895.52 = 520,896
520,896 copies have been sold to date