it takes twice as much as time to travel from City A to City C by bus as by train. How long, in kilometers, does the bus take from City A to City C?
(1) The train averages 85 kilometers per hour and takes 2.5 hours to travel from City A to City C.
(2) The bus average 45 kilometers per hour.
The answer is C
The question doesn't tell you that the train and the bus travel the same path, so statement (1) is not sufficient.
Statement (2) by itself is obviously insufficient
You know that the bus takes twice as long as the train. According to statement (1), the bus takes 5 hours. Since statement (2) gives you the bus's rate. Therefore both of them combined give you the answer.