Answer:
He drinks 21/4, or 5 1/4, liters of tea in 1 hour
Explanation:
The following question is missing: How much does he drink in one hour?
Given that he drinks 3 1/2 (= 7/2) liters of tea every 2/3 of an hour, and we want to know how much he drink in 1 hour, then the following proportion must be satisfied:
7/2 liters / x liters = 2/3 hour / 1 hour
x = (7/2)/(2/3) = 7/2 * 3/2
x = 21/4 = 5 1/4 liters