Calculate the speed of a boat in still water (in km/hr) if in one hour, the boat goes 10 km/hr downstream and 4 km/hr upstream. Choose the correct choice: A) 7 kmph B) 8 kmph C) 9 kmph D) 7 kmph E) 6 kmph

Rationale: speed in still water = ( 10 + 4 ) 1 / 2 kmph = 7 kmph . answer : a
Answer: A