Your answer would be 3.75.
(x cookies) / (23 students - (12/2) students) = 2 cookies per student
[x / (23 - 6)] cookies per student = 2 cookies per student
23 students * (2 cookies per students) - 12 cookies = x cookies
The "students" unit cancels
46 cookies - 12 cookies = x cookies
x cookies = 34 cookies
Resultado:









Iris al principio tenía 40 soles.
Espero que te sirva, salu2!!!!