Answer:
1 hour and 42.85 minutes.
Step-by-step explanation:
It is found from the process of reviewing that experience survey a roadbed in 3 hours.
Hence, in 1 hour the experience survey of the roadbed.
Again, it is found that the apprentice survey needs 4 hours to survey the same stretch of road.
So, in 1 hour the apprentice survey does of the roadbed survey.
If they work together then in 1 hour, the survey work will be done by ()=
parts.
Therefore, the total survey they will complete working together in hours i.e. 1 hour and 42.85 minutes. (Answer)