Two hard physics problems (Projectile motion and gravitation), for me

Homework Statement

Please refer to the figures. (The first one is multiple-choice, the latter is structured).

Homework Equations

For the first problem:
u = √(2gH)
x = uxsinθt + $\frac{1}{2}$gsinθt2
uycosθt = $\frac{1}{2}$gcosθt2 and maybe others
u = initial velocity
x = x-displacement (along the slope)
y = y-displacement (perpendicular to slope)

For the second:
FG= Gm1m2 / r2
m are masses
FG = gravitational attractive force between two masses
$G\ =\ 6.673(10)\ \times\ 10^{-11}\ m^{3} kg^{-1} s^{-2}$

and maybe others

The Attempt at a Solution

Sorry, I've been doing these two problems for hours, still can't get the answers:

For the first, I only found that the time between the release and the first impact might be √(2H/g).

For the second problem I even dont any idea about how to solve it:(

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