Answer:
One piece is 26 inches long while the other is 52 inches long.
We let:
x = one piece of the thread
2x = the other piece of the thread
Since the thread is 78 inches long,
2x + x = 78
Solve for x:
[tex]2x+x=78\Rightarrow3x=78[/tex][tex]\frac{3x}{3}=\frac{78}{3}\Rightarrow x=26[/tex]Since one piece of the thread is 26 inches long, the other piece would be:
[tex]2x=2(26)=52[/tex]The other piece would be 52 inches long.