Well, to find this out, lets find out how much is taken each day:
6 hours x 4 = 24 hours (Or one day)
So because we multiplied the hours by 4, we also multiply the dosage by 4:
.5 ts x 4 = 2 ts
That means every day, 2 teaspoons is taken by the child.
Then we figure out how many teaspoons of medicine there is in 24 doses:
If .5 ts = 1 dose, then 12 ts= 24 doses because half a teaspoon is 1 dose.
So if there are 12 ts and and 2 ts are taken each day, then that means the final answer is:
The medicine will last 6 days.
Hope this helps!