1. The villages "Upper Vasyuki" and "Lower Vasyuki" are located on the bank of a river. A steamboat takes one hour to travel from Upper Vasyuki to Lower Vasyuki, while a motorboat takes 45 minutes. It is known that the speed of the motorboat in still water is twice the speed of the steamboat (also in still water). Determine how long (in minutes) it will take for a raft to drift from Upper Vasyuki to Lower Vasyuki?
Answer: 90 minutes.

Solution: Let's take the distance between the villages as a unit of length (unit). Then the speed of the steamboat downstream is 1 unit/h, and the speed of the motorboat is $4 / 3$ units/h. Therefore, the own speed of the steamboat is $1 / 3$ units/h, from which the speed of the current is $2 / 3$ units/h. Therefore, the raft will travel a distance of 1 unit in $3 / 2$ hours.