7.4. The monkey becomes happy when it eats three different fruits. What is the maximum number of monkeys that can be made happy with 20 pears, 30 bananas, 40 peaches, and 50 tangerines?
7.4. Let's set the tangerines aside for now. There are $20+30+40=90$ fruits left. Since we feed each monkey no more than one tangerine, each monkey will eat at least two of these 90 fruits. Therefore, there can be no more than $90: 2=45$ monkeys. We will show how to satisfy 45 monkeys:

5 monkeys eat a pear, a banana, and a tangerine;

15 monkeys - a pear, a peach, and a tangerine; 25 monkeys - a peach, a banana, and a tangerine.

Answer: 45 monkeys.