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Medicine Half Life

Age 14 to 18
Challenge Level
A certain medicine is broken down by the body so that half of the remaining dose in the system is broken down every 12 hours. 
If I regularly take 400mg of medicine in the morning and 400mg of medicine in the evening what is the long term effective level in my system after I take each tablet?
 
Extension: What will be the long term stable level after I take each tablet if the body breaks down half of the remaining dose every 6 hours?
 
Did you know ... ?

The 'half-life' of medicines is an important concept in medicine, particularly in the area of anti-depressants which take some time to reach active levels in the body.