Could you show how much it is?
For the sake of the argument:
test accuracy: exactly 99.0% accurate
disease incidence: exactly 1 in 1 million
For the sake of simple calculations, let's assume we test exactly 1 million people.
tests positive = (1 * 0.99) + (999999 * 0.01)
tests positive = (.99) + (9999.99)
tests positive = 10000.98
While true in the real world this wasn't part of the problem as written above!
But if only one rate is given, that indicates they're equal. If they're not, then it's reasonable to describe the documentation as incorrect.
Consider a population of 100M people, of which 100 would have the illness. Of them, 99% = 99 would test positive and 1% = 1 would test negative. For the other 99,999,900 healthy people, 99% = 98,999,901 would test negative and 1% = 999,999 would test positive.
In total, 99 + 999,999 people would test positive. Given that a person tests positive, then, there is only a 99 / (99 + 999,999) ~= 0.01% chance that person has the illness.
A solution would be repeated retesting, as the 1st, 2nd, 3rd, and 4th consecutive positive test results would lead to 0.01%, 1%, 50%, and 99% chances. (Each additional positive test reduces the false positives by 100-fold, whereas the ill patients are very likely to get continually positive results.)