Let x be the money he had originally.
x/3+5=x/2
5=x/6
x=30
So he had $30 originally.
I really don't think you wrote the question properly. Or maybe you did, but this question doesn't make any sense! :/
Answer:
25%
Step-by-step explanation:
Total= 40 students
boys +girls= 40
30 +girls= 40
number of girls
= 40 -30
= 10
Percentage of girls

Alternatively,
percentage of girls
= 100% -(percentage of boys)
