 
<translate> Saurin saukar da ruwa = d/t = 90/(2 1/2) = 36 kmph Saurin hawan sama = d/t = 45/(2 1/2) = 18 kmph Saurin rafin = (36 - 18) / 2 = 9 kmph Saboda haka, amsar ita ce (A). <eng> Speed downstream = d/t = 90/(2 1/2) = 36 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (36 - 18)/2 = 9 kmph
Therefore, the answer is (A). 