Answer:
Length of old board = 68.2cm
Step-by-step explanation:
Let old board length be x
Given new board is 120 % longer than old board = x + 120% of x
Length of new board = 150cm
Therefore,
x + 120% of x = 150
[tex]x + \frac{120}{100} x = 150\\\\x + 1.20x = 150\\\\2.2x = 150 \\\\x = 68.18 = 68.2cm[/tex]
