Question

the ratio of the number of adults to the number of children in a library is 12:5 if there are 45 children in the library how my adults are there at the library.

Answer 1

There will be 108 adults.
Since the number of children are 45 and the ratio of adults to children is 12:5, divide 45/5. That equals 9.
So since you have that down, multiply 12x9. That equals 108.

Answer 2

I’m guessing 108. 45 divided by 5 is 9, so 9 times 12 is 108.