1.10$for the bat and the ball together
Your guess
A bat and a ball cost $1.10, the bat $1 more than the ball. How much is the ball?
More about it
The puzzle is part of the Cognitive Reflection Test, introduced by Shane Frederick in 2005. Students overwhelmingly give the wrong answer. But those who get it wrong are less confident than on an equivalent puzzle without the trap: we sense that something is off.
