8 pounds of chamomile tea must be mixed to make a mixture that costs 14.63 per pound.
Explanation:
We are given the following in the question:
Chamomile tea:
Unit cost = 18.20 per pound
Amount = x pounds
Total cost =

Orange tea:
Unit cost = 12.25 per pound
Amount = 12 pounds
Total cost =

Total mixture:
Unit cost = 14.63 per pound
Amount = (12+x) pounds
Total cost =

We can write the equation that cost of mixture is equal to cost of chamomile tea and orange tea.

Thus, 8 pounds of chamomile tea must be mixed to make a mixture that costs 14.63 per pound.