Questions 25 and 26 are based on the following description.
Amabagamuwa and Dambagamuwa are two suburbs separated by a river. The road connecting these two suburbs is 4 km long and it has a bridge in the middle. Speed limits are specified as 20 km h^-1 on the bridge and 60 km h^-1 on the road except on the bridge.
What is the minimum time required to go from Ambagamuwa to Dambagamuwa, if a vehicle needs to go the entire journey in uniform speed?