A train travels at an average speed of 40 km per hour for $$3\frac{1}{2}$$ h and then travels at a speed of 60 km per hour for $$2\frac{1}{2}$$ h. How far does the train travel in the ent ire 6 h?

A

215 km

B

245 km

C

270 km

D

290 km