IKMC 2027 - Grades 5-6 - Self-study SET 7 - Thematic Batch 3 Question 21

The ruler of the forest needs parrot interpreters who speak at least one of three languages: reptile, mammal and insect. Twenty parrots qualify. Six speak only reptile, eight speak mammal and nine speak insect.

1. How many speak mammal or insect?
2. How many speak both mammal and insect?
3. How many speak all three languages, given that two speak exactly the two languages mammal and insect?