Answer: 24 oz per day
Explanation:
Hi, to answer this question, first, we have to calculate the amount of coffee he has per day. 
4 cups x 80z = 32oz 
Now, we have multiply the result by the percentage in decimal for (25% = 25/100) 
32 x (25/100) = 8 
Finally subtract the percent amount to the amount of coffee per week. 
32-8 = 24 oz per day 
 Feel free to ask for more if needed or if you did not understand something.