$2+$ [ Motion problems $]$

Without a nut (from the hollow to the nut tree), the squirrel runs at a speed of 4 m/s, and with a nut (from the nut tree to the hollow) - at a speed of 2 m/s. For the round trip from the hollow to the nut tree and back, she spends 54 seconds. Find the distance from the hollow to the nut tree.
Since the squirrel runs back at half the speed, the time spent on the return trip is twice the time spent on the trip from the tree hole to the nut grove. Therefore, the time spent on the trip from the tree hole to the nut grove is one third of the total time, which is $54: 3=18$ seconds. Thus, the distance from the tree hole to the nut grove is $18 \cdot 4=72$ m.

## Answer

$72 \mathrm{m}$.