In one hour, a boat goes 11 km along the steram and 5 km against the stream. The speed of the boat in still waer (in km/hr) is:
Choose the correct answer:
A) 2 B) 4 C) 8 D) 12 E) 15

Rationale: sol . speed in still water = 1 / 2 ( 11 + 5 ) kmph = 8 kmph . answer c
Answer: C