This type of example was analyzed in another very recent help request. Go to that one and study it. The strategy can be this:
Assign variables to all numbers, both known and unknown.
Arrange a data table.
Form a system of equations.
Solve the system.
The basic concept is travel rates in the fact, RT=D to relate rate, time, distance. The data table should be of this form:
RATE TIME DISTANCE
UPSTREAM () () ()
DOWNSTREAM () () ()
No different from the other exercise problem ; just different given values.