More physics acceleration questions please help. (immediate best answer)

1) Two soccer players start from rest, 58 m apart. They run directly toward each other, both players accelerating. The first player has an acceleration whose magnitude is 0.50 m/s2. The second player's acceleration has a magnitude of 0.30 m/s2.
(a) How much time passes before they collide?

(b) At the instant they collide, how far has the first player run?

2)A ball is thrown straight upward and rises to a maximum height of 38 m above its launch point. At what height above its launch point has the speed of the ball decreased to one-half of its initial value?

3)From her bedroom window a girl drops a water-filled balloon to the ground, 6.9 m below. If the balloon is released from rest, how long is it in the air?

1) let the distance from the 1st player be x , and by using x = Vot + 1/2at^2 u get :

x = 0 + 1/2 (0.5) t^2 --- (1)

58 - x = 0 + 1/2 (0.3) t^2 --- (2)

add these 2 eqn to find t :

=> 58 = t^2 (0.25 + 0.15)

=> t^2 = 145 => t = 12 s (approx)

hence x = 0.5^2 x 12^2 = 36 m (approx)

b) V = Vo + at

=> V = 0 + 0.5 (12) = 6 m/s

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2) let init speed = Vo , at max h V = 0 , so :

0 = Vo^2 - 2gh => h = Vo^2 / 2g

hence Vo = sqrt (2gh) = 27.3 m/s

half the value = 13.65 m/s

so (13.65)^2 = (27.3)^2 - 2g h2

=> h2 = 28.5 m

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3) 6.9 = 0 + 1/2 g t^2

=> t = 1.2 s