Jerry had 12 action figures and 40 books on a shelf in his room. Later he added 12 more action figures to the shelf. How many more books than action figures were on his shelf?
Jerry had 12 action figures and 40 books on a shelf in his room. 

This means that the ratio of action figures to books is 12:40, or 1:3.5. 

Later he added 12 more action figures to the shelf. 

This means that the ratio of action figures to books is now 24:40, or 1:1.67. 

To find out how many more books than action figures were on his shelf, we need to subtract the new ratio from the old ratio. 

1:1.67 - 1:3.5 = -2.83

This means that there are 2.83 more books than action figures on Jerry's shelf.