Problem 5 · 2010 Math Kangaroo
Medium
Logic & Word Problems
The managing director of a company claims “Every one of our employees is at least 25 years old.” It turns out, he is wrong. Which of the following statements is correct?
Show answer
Answer: D — One of the employees of the company is less than 25 years old.
Show hints
Hint 1 of 2
The boss's 'every employee is at least 25' is false.
Still stuck? Show hint 2 →
Hint 2 of 2
The exact opposite of 'all are at least 25' is just one counterexample.
Show solution
Approach: negate a universal statement
- 'Every employee is at least 25' being wrong means the claim fails for someone.
- The negation of 'all ≥ 25' is 'at least one is below 25'.
- So one employee is less than 25 years old.
Mark:
· log in to save