The question is not complete. I have assumed you want to calculate the length of each piece.
Answer:
The shortest piece is 4 inches long
The longest piece is 8 inches long
Step-by-step explanation:
Equations
One piece of tubing is two times the other.
Let's call
x=the shortest piece of tubing
2x=the longest piece of tubing
The total length of the piece of tubing is 12 inches, thus:
x + 2x = 12
Simplifying:
3x = 12
Dividing by 3:
x = 12 / 3 = 4
x=4, and 2x=8, thus:
The shortest piece is 4 inches long
The longest piece is 8 inches long
