Answer:
First piece = 30m , 2nd is 120 m and third piece is 240 m long.
Explanation:
Let the length of the first piece be x m.
Then the length of the second piece = 4x m.
The third piece = 2 * 4x = 8x m.
So x + 4x + 8x = 390
13x = 390
x = 30 m
So 2nd piece = 4*30 and third is 8*30 m.