How old is Alex?

• A. 12
• B. 10
• C. 14
• D. 11

Answer: (A)

Solving this type of question comes down to turning the age clues into simple arithmetic. You identify how Alex’s age relates to other facts in the prompt—whether Alex is a certain number of years older than someone else or how old Alex would be after some amount of time—and you set up equations from those relationships. Then you solve for Alex’s age and check that the value satisfies every clue given. When you work through the clues in this item, the age that fits all the conditions is 12. That’s the number that makes all the stated relationships true, so it’s the correct result. If you test other ages, at least one clue won’t hold when you substitute it back in.