Question 3
A ship travels from $A$ to $B$ at a planned constant speed. After part of the journey, an engine problem is discovered and the driver proposes reducing the speed by $25\%$ of its original value. The captain calculates that doing so immediately would make the ship arrive $1$ hour $20$ minutes late, beyond the allowed delay. Instead, he orders it to travel another $40$ km at its original speed before making the proposed reduction; it then arrives $1$ hour late. Find the ship\'s planned speed.
