33%

Together, a racket and a ball cost a total of $1.10. The racket costs exactly $1 more than the ball. What does the ball cost?

Fact Lab

Interesting fact:

If you tied all the nerve tracts in an adult human body together from end to end, you'd end up with a thread that is 5.8 million kilometres in length – enough to swathe the earth 145 times, or to stretch 15 threads between Earth and the moon.