If a boat is rowed downstream for 24 km in 4 hours and upstream for 48 km in 24 hours, what is the speed of the boat and the river?
Select the correct option.
A) 4 , 3	B) 4 , 4	C) 3 , 3	D) 4 , 5	E) 4 , 2

Rationale: "explanation : if x : speed of boats man in still water y : speed of the river downstream speed ( ds ) = x + y upstream speed ( us ) = x â € “ y x = ( ds + us ) / 2 y = ( ds â € “ us ) / 2 in the above problem ds = 6 ; us = 2 x = ( 6 + 2 ) / 2 = 8 / 2 = 4 km / hr y = ( 6 - 2 ) / 2 = 4 / 2 = 2 km / hr answer : e"
Answer: E