Castel made a trip to the ferry office and back. on the trip there he traveled 60 km/h and on the return trip he went 45 km/h. how long did the trip there take if the return trip took four hours?

Assuming Castel takes the same route going out and on the return, the distance will be the same

We have:
Speed going out = 60 km/h
Speed return = 45 km/h
Time return = 4 hours

Distance return = 45 × 4 = 180 km

Return distance = Distance of travel out

180 = 60 × time
Time = 180 ÷ 60
Time = 3 hours