 
 <translate> Speed upstream = 27/9 = 3 kmph
Speed down stream = 81/3 = 27 kmph
Speed of stream = ½ (27-3) = 12 kmph So the final answer is (A). <hau> Saurin hawan sama = 27/9 = 3 kmph Saurin saukar da rafi = 81/3 = 27 kmph Saurin rafi = 1⁄2 (27-3) = 12 kmph Saboda haka amsar karshe ita ce (A). 