Answer:
515,493 copies sold
Explanation:
Since this is a ratio problem and we have three values and one variable that we need to find (copies sold to date) then we can use the Rule of three to solve this problem. We simply need to multiply the diagonal values and divide by the third value to get the variable. This can be seen below...
36,600 copies <=====> 7.1%
x copies <========> 100%
(36,600 * 100) / 7.1 = 515,492.96
Since the number of books cannot be a decimal we must round up to the nearest book sold, which would mean that the number of copies sold to date is 515,493 copies sold