x+ 12+2X/( 1- 1/ 1 1)= 156

The solution is X=45.

So the total number of girls is 45+ 12=57, and the total number of boys is 156-57=99.

If you don't understand this question, you can ask. If you are satisfied, please click on "Adopt as Satisfied Answer" in the upper right corner.

If you have any other questions, please adopt this question, and then post and click on my avatar to ask me for help. Not easy to answer, please understand, thank you.

Your adoption is the driving force of my service.

I wish you progress in your study!