Answer:
I got 40 an hour.
Explanation:
It matters little how many days she worked - she could have worked for 20 days, but if her hours all add up to 8 - then you simply divide the amount she earned by the number of hours (exluding taxes ;)
Still, if she worked for 6 days then she worked for 1.3 hours each day - or 1 and roughly 20 minutes (specifically 18 minutes).
320/8 = 40 so ... 40/h.