Answer
18 lengths
Work Step by Step
Given the trunk of the tree harvested for firewood is 27 ft and the farmer plans to cut it into 1$\frac{1}{2}$ft lengths before splitting
We need to find the number of lengths to be cut from it = 27 $\div$ 1$\frac{1}{2}$ ft
= 27 $\div$ $\frac{3}{2}$ ft
=27 x $\frac{2}{3}$
= 18 lengths