In a department of employees, speak French, speak Spanish, and speak neither French nor Spanish. How many employees speak both French and Spanish?
Answer: 20 employees
Answer
20
Subtracting the 10 employees who speak neither language from the total of 90 leaves 80 employees who speak at least one language. By the principle of inclusion-exclusion, Total(At least one) = French + Spanish - Both. Substituting the known values gives 80 = 55 + 45 - Both, which simplifies to 80 = 100 - Both, so Both = 20.
Step-by-Step Solution
Key Concept
Principle of Inclusion-Exclusion for Two Sets
Estimated Time:45s