Answer:
The length of the longest section x = 36 ft
Step-by-step explanation:
Total length of the wire = 51 ft
Let first section of wire = x
Second section of wire = y
Third section of wire = z
According to given data
x = 3 y & y = 4 z
Total length of the wire = x + y + z = 51
y = 12
x = 3 × 12 = 36
Therefore the length of the longest section x = 36 ft
