Respuesta :

Answer:

1st= 1

2nd =2

3rd =3

4th = 4

Step-by-step explanation:

Let's make an equation.

1) x

2) x+1

3) x+2

4) x+3

2*[(x+1+x+2+x+3)-x]=16

2*[(3x+6)]-x]=16

2[2x+6]=16

4x+12=16

4x=4

x=1