Question 230368
We need to have 3 variables (x,y,z) representing the numbers and three equations representing the conditions.

Eqn 1: x+6=y
Eqn 2: 3x=z
Eqn 3: x+y+z=26

Substitute the Eqn's 1 and 2 into Eqn 3 so that the only variable is x:

x+(x+6)+3x=26
5x+6=26
5x=20
x=4

Find y:

Eqn 1: x+6=y
4+6=y
y=10

Find z:

Eqn 2: 3x=z
3*4=z
z=12

The three numbers are x=4, y=10, and z=12.