Respuesta :

texaschic101
x = 6th graders
y = 7th graders

x + y = 57
x = 2y

2y + y = 57
3y = 57
y = 57/3
y = 19 <=== there are 19 seventh graders

x = 2y
x = 2(19)
x = 38 <==== there are 38 sixth graders