# RE7 | perplexity/sonar-pro | run 1

## Prompt

A bat and a ball cost $1.10 together. The bat costs $1.00 more than the ball. How much does the ball cost?

## Response

The ball costs **$0.05** (5 cents). The bat then costs **$1.05**, so together they are $1.10 and the bat is exactly $1.00 more than the ball.[2](https://www.psychologicalscience.org/publications/observer/obsonline/a-new-twist-on-a-classic-puzzle.html)

## Quick reasoning

Let the **ball** cost \(x\) dollars.

- The bat costs **$1.00 more**, so bat = \(x + 1\).[2](https://www.psychologicalscience.org/publications/observer/obsonline/a-new-twist-on-a-classic-puzzle.html)  
- Together they cost $1.10, so:
  \[
  x + (x + 1) = 1.10
  \]
  \[
  2x + 1 = 1.10
  \]
  \[
  2x = 0.10
  \]
  \[
  x = 0.05
  \]

So the **ball = $0.05** and the **bat = $1.05**.[1](https://www.reddit.com/r/confidentlyincorrect/comments/vfqwiz/a_bat_and_a_ball_are_110_and_the_bat_is_1_more/)[3](https://www.reddit.com/r/askmath/comments/1qjvrop/my_friend_gave_me_a_math_chalange_but_he_says_my/)

Many people initially answer “10 cents” for the ball, but that would make the bat $1.10 and the total $1.20, which contradicts the problem.[2](https://www.psychologicalscience.org/publications/observer/obsonline/a-new-twist-on-a-classic-puzzle.html)[5](https://www.theguardian.com/science/2020/oct/19/can-you-solve-it-the-bat-the-ball-and-the-bamboozle)

Would you like to see a couple of similar puzzles that use the same kind of reasoning?
