First bundle: 2x
Second bundle: 5x
Third bundle: 7x
Total length = 840 meters
Equation:
2x + 5x + 7x = 840
14x = 840
14x/14 = 840/14
x = 60
Substitute 60 for x:
First bundle: 2x = 2 (60) = 120 meters
Second bundle: 5x = 5 (60) = 300 meters
Third bundle: 7x = 7 (60) = 420 meters
Check:
120 m + 300 m + 420 m = 840 meters.