20. Suppose you need to re-administer this injection at the point when the concentration is less than 0.5%. If the first injection was given at 8:00 am, what time should the next injection be given?

20. Suppose you need to re-administer this injection at the point when the concentration is less than 0.5%. If the first injection was given at 8:00 am, what time should the next injection be given?