Answer:
The answer is [tex]\frac{18}{29}[/tex]
Explanation:-
Total number of students = 12 + 18 = 30
Total number of students after one girl left = 29
Number of boys = 18
Probability that a boy raises his hand and asks to go to the bathroom =
Number of boys divided by total number of students
[tex]\frac{18}{29}[/tex]