Answer:
Length of other board
metres
Step-by-step explanation:
Given: Length of board =
metres
Length of board was divided into two.
Length of one piece =
metres
Let
= length of the other board
Length of the other board = Length of board - Length of one piece
So, 

Thus, length of the other board
metres
im pretty sure the answer is C
From the text of the task we can write the equation: