Distance = 120 km
Velocity V1 = V2 - 4 km/h
then
120 - X = Y
Time T= 3 hours
T= V1 / (120 - X)
also
T= V2/ (X)
Now solve this 2x2 system
3•(120-X) = V1
3X = V1 + 4
then
360 - 3X = 3X - 4
364/6 = X
60. 6 = X
Now find V2= 3• 364/6= 182 km/h
and
V1= 182-4= 178
Then answer is
rate of ciclist are
V2= 182 km/h
V1 = 178 km/h