Respuesta :

caylus

Hello,

Let's x then number of students.

x is divisible by 12,15,18 thus by 180 (lcm)

x=180*k is a square

2²*3²*5*k= a square ==> k=5

x=180*5=900

Proof:

900/12=75

900/15=60

900/18=50

900=30²