Initially number of matches $= 40$ Now matches won $= 12$ Now let remaining matches be $x$ Now number of matches won $= 0.6x $ Now as per the condition : ${12 + 0.6x}/{40 + x} =1/2 $ $4 +1.2x=40+x $ $0.2x=16 $ $x=80$ Now when they won 90% of remaining = $80(0.9) =72 $ So total won $= 84 $