Respuesta :

The unknowns : number of boys (b) and number of girls (g)

b + g = 23
g = b + 7

b + b + 7 = 23
2b + 7 = 23
2b = 23 - 7
2b = 16
b = 16/2
b = 8 <=== there are 8 boys

g = b + 7
g = 8 + 7
g = 15 <=== there are 15 girls